Discrete-time Survival Analysis Research Articles

Estimating Gender Differences in the Association between Cognitive Resilience and MCI Incidence.

Recent evidence suggests that the influence of verbal intelligence and education on the onset of subjective cognitive decline may be modulated by gender, where education contributes less to cognitive resilience in women than in men. This study aims to examine gender differences in the association between cognitive resilience (CR) and mild cognitive impairment (MCI) incidence in an Australian population-based cohort. We included 1806 participants who had completed at least the first two waves and up to four waves of assessments in the Personality and Total Health (PATH) through life study (Baseline: 49% Female, Mage=62.5, SD=1.5), age range=60-66). CR proxies included measures of educational attainment, occupation skill, verbal intelligence, and leisure activity. Discrete-time survival analyses were conducted to examine gender differences in the association between CR proxies and MCI risk, adjusting for age and Apolipoprotein E4 status. Gender differences were only found in the association between occupation and MCI risk, where lower occupation skill was more strongly associated with higher risk in men than in women (OR = 1.30, 95% CI[1.07, 1.57]). In both genders, after adjusting for education and occupation, one SD increase in leisure activity was associated with lower MCI risk by 24% (OR = 0.76, 95% CI[0.65, 0.89]). Higher scores in verbal intelligence assessment were associated with reduced risk of MCI by 22% (OR = 0.78, 95% CI[0.69, 0.89]). Occupational experience may contribute to cognitive resilience differently between genders. Life-course cognitive engagement and verbal intelligence may be more protective against MCI than education and occupation for both men and women.

Predicting the onset of myopia in children by age, sex, and ethnicity: Results from the CLEERE Study.

Clinicians and researchers would benefit from being able to predict the onset of myopia for an individual child. This report provides a model for calculating the probability of myopia onset, year-by-year and cumulatively, based on results from the largest, most ethnically diverse study of myopia onset in the United States. This study aimed to model the probability of the onset of myopia in previously nonmyopic school-aged children. Children aged 6 years to less than 14 years of age at baseline participating in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study who were nonmyopic and less hyperopic than +3.00 D (spherical equivalent) were followed up for 1 to 7 years through eighth grade. Annual measurements included cycloplegic autorefraction, keratometry, ultrasound axial dimensions, and parental report of children's near work and time spent in outdoor and/or sports activities. The onset of myopia was defined as the first visit with at least -0.75 D of myopia in each principal meridian. The predictive model was built using discrete time survival analysis and evaluated with C statistics. The model of the probability of the onset of myopia included cycloplegic spherical equivalent refractive error, the horizontal/vertical component of astigmatism (J0), age, sex, and race/ethnicity. Onset of myopia was more likely with lower amounts of hyperopia and less positive/more negative values of J0. Younger Asian American females had the highest eventual probability of onset, whereas older White males had the lowest. Model performance increased with older baseline age, with C statistics ranging from 0.83 at 6 years of age to 0.92 at 13 years. The probability of the onset of myopia can be estimated for children in the major racial/ethnic groups within the United States on a year-by-year and cumulative basis up to age 14 years based on a simple set of refractive error and demographic variables.

Reviving Decades-Old Wisdom: Longitudinal Analysis of Renin-Angiotensin System Inhibitors and its effects on Acute Ischemic Stroke to Improve Outcomes.

While Renin-Angiotensin System (RAS) inhibitors have a longstanding history in blood pressure control, their suitability as first-line in-patient treatment may be limited due to prolonged half-life and kidney failure concerns. Using a cohort design, we assessed the impact of RAS inhibitors, either alone or in combination with beta-blockers, on mortality, while exploring interactions, including those related to end-stage renal disease and serum creatinine levels. Eligible subjects were AIS patients aged 18 or older with specific subtypes who received in-patient antihypertensive treatment. The primary outcome was mortality rates. Statistical analyses included cross-sectional and longitudinal approaches, employing generalized linear models, G-computation, and discrete time survival analysis over a 20-day follow-up period. In our study of 3058 AIS patients, those using RAS inhibitors had significantly lower in-hospital mortality (2.2%) compared to non-users (12.1%), resulting in a relative risk (RR) of 0.18 (95% CI 0.12-0.26). Further analysis using G-computation revealed a marked reduction in mortality risk associated with RAS inhibitors (0.0281 vs. 0.0913, Risk Difference (RD) of 6.31% or 0.0631, 95% CI 0.046-0.079). Subgroup analysis demonstrated notable benefits, with individuals having creatinine levels below and above 1.3mg/dL exhibiting statistically significant RD (RD -0.0510 vs. -0.0895), and a significant difference in paired comparison (-0.0385 or 3.85%, CI 0.023-0.054). Additionally, longitudinal analysis confirmed a consistent daily reduction of 0.93% in mortality risk associated with the intake of RAS inhibitors. RAS inhibitors are associated with a significant reduction in in-hospital mortality in AIS patients, suggesting potential clinical benefits in improving patient outcomes.

The retention and attrition of early-career music teachers: a survival analysis

Over 30 states have experienced a shortage of music teachers in the past decade. The attrition of early-career teachers is one of the largest contributing factors to the rising demand for teachers nationally, but there is a lack of rigorous empirical research examining characteristics associated with attrition of music teachers. I leveraged data from the Maryland Longitudinal Data System to examine early-career music teachers’ retention and attrition patterns between 2013 and 2020 using descriptive statistics and discrete-time survival analysis (N = 6430). On average, 74% of early-career music teachers retained their current position each year, 8% moved to a different school in Maryland, and 18% of left public school music teaching in Maryland. Survival analysis indicated that half of all music teachers left public-school music teaching in Maryland within their first five years of teaching. Attrition risk was greatest in years two and three. Other factors associated with attrition risk included sex, race, ethnicity, school grade level, aspects of school culture, the student body, school and district urbanicity, and the number of teachers employed by the school district. Discussed policy recommendations include mentorship programs, teacher compensation, school resources, comprehensive family leave, and music teacher recruitment.

Risk of Primary Incident Hepatitis C Infection Following Bacterial Sexually Transmissible Infections Among Gay and Bisexual Men in Australia From 2016 to 2020.

In Australia, the incidence of hepatitis C virus (HCV) has declined among gay and bisexual men (GBM) with human immunodeficiency virus (HIV) since 2015 and is low among GBM using HIV preexposure prophylaxis (PrEP). However, ongoing HCV testing and treatment remains necessary to sustain this. To assess the potential utility of sexually transmissible infections (STIs) to inform HCV testing among GBM with HIV and GBM using PrEP, we examined the association between bacterial STI diagnoses and subsequent primary HCV infection. Data were from a national network of 46 clinics participating in the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance. GBM included had ≥1 HCV antibody negative test result and ≥1 subsequent HCV antibody and/or RNA test. Discrete time survival analysis was used to estimate the association between a positive syphilis, rectal chlamydia, and rectal gonorrhea diagnosis in the previous 2 years and a primary HCV diagnosis, defined as a positive HCV antibody or RNA test result. Among 6529 GBM with HIV, 92 (1.4%) had an incident HCV infection. A prior positive syphilis diagnosis was associated with an incident HCV diagnosis (adjusted hazard ratio, 1.99 [95% confidence interval, 1.11-3.58]). Among 13 061 GBM prescribed PrEP, 48 (0.4%) had an incident HCV diagnosis. Prior rectal chlamydia (adjusted hazard ratio, 2.75 [95% confidence interval, 1.42-5.32]) and rectal gonorrhea (2.54 [1.28-5.05]) diagnoses were associated with incident HCV. Diagnoses of bacterial STIs in the past 2 years was associated with HCV incidence. These findings suggest that STIs might be useful for informing HCV testing decisions and guidelines for GBM with HIV and GBM using PrEP.

Type-switching of short-acting nicotine replacement therapy products and its implications for treatment

IntroductionThe frequency with which people change from one medical treatment to another partly reflects satisfaction with the initial intervention. In this secondary analysis of observational data, we explore switch rates for short-acting nicotine replacement therapy (NRT) products, which differ in mode of use, rapidity of action, and adverse effect profiles. MethodsWe analyzed data from 46,882 participants in the Smoking Treatment for Ontario Patients program who received short-acting NRT (gum, lozenge, oral spray, or inhaler) at their initial visit. We used discrete-time survival analysis to model the time elapsing before a change was made to another product and included time-by-product interactions to explore differences over time and product-by-previous-quit-attempts interactions to examine the importance of potential previous exposure to NRT. We adjusted both models for a range of sociodemographic and tobacco use variables. ResultsOverall, 37.9% (95% CI = 37.5%, 38.4%) of participants switched to a different product at their first follow-up visit. Time-averaged and adjusted switch probabilities were 21.1% for gum, 23.8% for lozenge, 26.0% for inhaler, and 28.8% for oral spray. Switch rates were highest for people without past quit attempts, for women, and for people also using the nicotine patch. ConclusionsPeople frequently switch from one type of short-acting NRT to another. We did not assess reasons for switching, but they may include adverse effects, impracticality, and perceived ineffectiveness. Given the superior effectiveness of combination treatment, making multiple products available may improve outcomes by allowing some people to continue with short-acting products for longer.

Physical Activity, Social Participation, and Pain Outcomes Among Community-Dwelling Older Adults

BackgroundLittle is known regarding the effect of social participation (SP) and physical activity (PA) on pain outcomes among community-dwelling older adults in the United States. AimsTo determine whether SP and PA are associated with pain outcomes (bothersome pain and number of pain sites). DesignGuided by the biopsychosocial model of chronic pain for older adults, we analyzed data from 7,187 community dwelling participants in the National Health and Aging Trends Study. In cross-sectional analyses, we utilized logistic and negative binomial regressions. MethodsWe prospectively assessed the association between SP/ PA and new or worsening pain from baseline (2011) to 2021 using a discrete time survival analysis by logistic regression, controlling for sociodemographic and health characteristics. ResultsAt baseline, participation in 5 SP activities per month versus no activities, and performing any PA compared with no PA were significantly associated with lower likelihood of bothersome pain. Although SP and PA were associated with reporting fewer pain sites at baseline, SP was not associated with developing new or worsening pain, prospectively. However, walking and vigorous exercise compared with no PA was significantly associated with a 10% lower risk of developing new or worsening pain (adj odds ratio 0.90, 95% confidence interval [CI] 0.82-0.98). ConclusionsPhysical activity but not social participation may protect against development of new or worsening pain. More research is needed to determine whether social activity can be beneficial for pain prevention and management. Efforts to promote physical activity among older adults may reduce risk of new or worsening pain.

Parenting, Peers, and Alcohol Use Initiation Among Black, White, and Black-White Adolescents: Evidence Using Discrete-Time Survival Analysis

ABSTRACT Alcohol use among Biracial adolescents remains understudied. This study examined how parenting and peer factors relate to age of alcohol use onset among Black, White, and Biracial Black-White adolescents and emerging adults. We used Add Health data to produce a final analytic sample of 13,528 adolescents who self-identified as White, Black, or Biracial Black-White. Discrete-time survival analysis implemented within logistic regression indicated Black adolescents showed the lowest probability of alcohol use onset by age 18, followed by Biracial adolescents, and White adolescents. The probability of alcohol use onset increased for Monoracial Black and White adolescents at ages 16, 18, and 21. Descriptively our model suggest that Biracial adolescents exhibit a sharp decline in their probability of alcohol use onset at age 16 and a sharp increase at age 21. However, this trend did not differ significantly from the other racial groups. Consistent with social control and learning theories, low parental acceptance, high parental control, and peer substance use were associated with alcohol use onset. Alcohol use onset trajectories differed for Monoracial and Biracial adolescents with Biracial individuals reporting greater alcohol onset in adulthood. Prevention efforts should continue to target parental acceptance, parental control, and peer substance use.

Marijuana and E-cigarette Initiation Among Adolescents: A Survival Analysis

PurposePrior literature suggests marijuana and e-cigarette initiation among adolescents is surpassing combustible cigarette uptake. Marijuana and nicotine co-use is also a concern as these products grow in popularity. Initiation trajectories for marijuana and e-cigarette products are not well understood, let alone how the use of one product may impact initiation susceptibility for the other. MethodsWe used national longitudinal data from the Population Assessment of Tobacco and Health study from 2013 to 2018. Eighth graders in Wave 1 made up the analytic sample (N = 2,270). We employed discrete time survival analyses to determine the likelihood of initiating marijuana and e-cigarettes between Waves 2 and 5. We used survival analyses to estimate the relationships between prior cigarette and marijuana use and subsequent e-cigarette initiation, as well as prior cigarette and e-cigarette use and subsequent marijuana initiation. ResultsPrevious marijuana initiation was associated with later e-cigarette initiation (odds ratio = 6.88, 95% confidence interval [4.89, 9.67]). Previous e-cigarette initiation was associated with later marijuana initiation (odds ratio = 9.28, 95% confidence interval [6.86, 12.56]). By wave 5, adolescents were more than 42% likely to initiate marijuana and e-cigarettes. DiscussionSusceptibility to marijuana and e-cigarette products starts as early as eighth grade and increases over time. The use of one product is significantly related to later initiation for the other. Rather than addressing marijuana and nicotine as separate concerns, interventions may benefit by recognizing the closely related nature of these products.

Timing matters: The contribution of running during different periods of the light/dark cycle to susceptibility to activity-based anorexia in rats

Individuals with anorexia nervosa (AN) exhibit dangerous weight loss due to restricted eating and hyperactivity. Those with AN are predominantly women and most cases have an age of onset during adolescence. Activity-based anorexia (ABA) is a rodent behavioral paradigm that recapitulates many of the features of AN including restricted food intake and hyperactivity, resulting in precipitous weight loss. In addition, there is enhanced sensitivity to the paradigm during adolescence. In ABA, animals are given time-restricted access to food and unlimited access to a running wheel. Under these conditions, most animals increase their running and decrease their food intake resulting in precipitous weight loss until they either die or researchers discontinue the paradigm. Some animals learn to balance their food intake and energy expenditure and are able to stabilize and eventually reverse their weight loss. For these studies, adolescent (postnatal day 33–42), female Sprague Dawley (n = 68) rats were placed under ABA conditions (unlimited access to a running wheel and 1.5 hrs access to food) until they either reached 25% body weight loss or for 7 days. 70.6% of subjects reached 25% body weight loss before 7 days and were designated susceptible to ABA while 29.4% animals were resistant to the paradigm and did not achieve the weight loss criterion. We used discrete time survival analysis to investigate the contribution of food intake and running behavior during distinct time periods both prior to and during ABA to the likelihood of reaching the weight loss criterion and dropping out of ABA. Our analyses revealed risk factors, including total running and dark cycle running, that increased the likelihood of dropping out of the paradigm, as well as protective factors, including age at the start of ABA, the percent of total running exhibited as food anticipatory activity (FAA), and food intake, that reduced the likelihood of dropping out. These measures had predictive value whether taken before or during exposure to ABA conditions. Our findings suggest that certain running and food intake behaviors may be indicative of a phenotype that predisposes animals to susceptibility to ABA. They also provide evidence that running during distinct time periods may reflect functioning of distinct neural circuitry and differentially influence susceptibility and resistance to the paradigm.

Prospective association of attachment style with suicide attempts among US Army soldiers.

Insecure attachment styles are associated with retrospectively reported suicide attempts (SAs). It is not known if attachment styles are prospectively associated with medically documented SAs. A representative sample of US Army soldiers entering service (n = 21 772) was surveyed and followed via administrative records for their first 48 months of service. Attachment style (secure, preoccupied, fearful, dismissing) was assessed at baseline. Administrative medical records identified SAs. Discrete-time survival analysis examined associations of attachment style with future SA during service, adjusting for time in service, socio-demographics, service-related variables, and mental health diagnosis (MH-Dx). We examined whether associations of attachment style with SA differed based on sex and MH-Dx. In total, 253 respondents attempted suicide. Endorsed attachment styles included secure (46.8%), preoccupied (9.1%), fearful (15.7%), and dismissing (19.2%). Examined separately, insecure attachment styles were associated with increased odds of SA: preoccupied [OR 2.5 (95% CI 1.7-3.4)], fearful [OR 1.6 (95% CI 1.1-2.3)], dismissing [OR 1.8 (95% CI 1.3-2.6)]. Examining attachment styles simultaneously along with other covariates, preoccupied [OR 1.9 (95% CI 1.4-2.7)] and dismissing [OR 1.7 (95% CI 1.2-2.4)] remained significant. The dismissing attachment and MH-Dx interaction was significant. In stratified analyses, dismissing attachment was associated with SA only among soldiers without MH-Dx. Other interactions were non-significant. Soldiers endorsing any insecure attachment style had elevated SA risk across the first 48 months in service, particularly during the first 12 months. Insecure attachment styles, particularly preoccupied and dismissing, are associated with increased future SA risk among soldiers. Elevated risk is most substantial during first year of service but persists through the first 48 months. Dismissing attachment may indicate risk specifically among soldiers not identified by the mental healthcare system.

Discrete-time survival analysis with survey weights: a case study of age at child death in Sierra Leone

BackgroundChild death rates are often regarded as reliable indicators for overall welfare of a country since they give insight of health accessibility and development. For planning and controlling purposes, it is important to understand which ages are at higher risks of experiencing child death as well as determinants thereof.MethodsWe used the Sierra Leone DHS 2019 data which was collected using two stage sampling methods. Data collection involved interviewing women aged from 15–49 to obtain information about children they had in the past up to 2019. Age at death of child was modelled using discrete-time survival analysis with a logit link at the same time applying survey weights. The analysis also sought to estimate the determinants of child death (under-five mortality). The baseline hazard was modelled with a polynomial function.ResultsResults showed that children from rural areas had significantly lower odds of dying compared with those from urban areas (odds ratio (OR) = 0.861, p-value = 0.0003). Children of mothers who were currently using contraceptives, and those whose mothers had been using since their last birth were at higher odds of child death compared to children whose mothers had never used contraceptives before (currently using: OR = 1.118, p-value = < .0001; used since last birth: OR = 1.372, p-value = < .0001). Children with no health insurance had significantly higher odds of death than those with health insurance (OR = 1.036, p-value = < .0001). Children of women who were married, and of women who were formerly married were at significantly higher odds of experiencing child death than children of women who had never been in union (married: OR = 1.207, p-value = 0.0003; formerly married: OR = 1.308, p-value = 0.0009 compared to those that have never been married). Increase in the age group of mothers increases the odds of their children experiencing child death compared to mothers in their teenage years (20-29: OR = 1.943, p-value = < .0001, 30-39: OR = 2.397, p-value = < .0001 and > = 40: OR = 2.895, p-value = < .0001 compared to mothers in their 15-19 years).ConclusionThe study provides evidence that residing in urban areas, marital union of the mother, children having no health insurance, use of contraceptives by mother, older ages of the mother and no health insurance significantly increase the odds of child death. This points out to a possible need for improved health infrastructure to be made available to citizens in all places of delivery and more awareness on pregnancy related complications.

A marginal structural model to estimate the effect of antidepressant medication treatment on major cardiovascular events among people with post-traumatic stress disorder.

Previous evidence on antidepressant medication and cardiovascular disease (CVD) among patients with posttraumatic stress disorder (PTSD) has been inconclusive. We estimated the association between antidepressant medication and CVD by applying a marginal structural model. We analyzed medical utilization records of 27 170 people with PTSD without prior major cardiovascular events in the Korean National Health Insurance Database (NHID). PTSD and CVD were defined in accordance with the recorded ICD-10 diagnostic codes. We acquired information on antidepressant use from the NHID and categorized them by medication type. A composite major adverse cardiovascular events (MACE) outcome was defined as coronary artery disease with revascularization, ischaemic stroke, and/or haemorrhagic stroke. We used inverse probability of treatment weighting to estimate the parameters of a marginal structural discrete-time survival analysis regression model, comparing the resulting estimates to those derived from traditional time-fixed and time-varying Cox proportional hazards regression. We calculated cumulative daily defined doses to test for a dose-response relationship. People exposed to antidepressants showed a higher hazard of MACE [hazard ratio (HR) 1.34, 95% confidence interval (CI) 1.18-1.53]. The estimated effects were strongest for selective serotonin reuptake inhibitors (HR 1.24, 95% CI 1.08-1.44) and TCAs (HR 1.33, 95% CI 1.13-1.56). Exposure to serotonin-norepinephrine reuptake inhibitors did not appear to increase the risk of MACE. People exposed to higher doses of antidepressants showed higher risk of MACE. In a national cohort of people with PTSD, exposure to antidepressant medications increased the risk of MACE in a dose-response fashion.

Temporal Clustering of Critical Illness Events on Medical Wards

Recognizing and preventing patient deterioration is important for hospital safety. To investigate whether critical illness events (in-hospital death or intensive care unit [ICU] transfer) are associated with greater risk of subsequent critical illness events for other patients on the same medical ward. Retrospective cohort study in 5 hospitals in Toronto, Canada, including 118 529 hospitalizations. Patients were admitted to general internal medicine wards between April 1, 2010, and October 31, 2017. Data were analyzed between January 1, 2020, and April 10, 2023. Critical illness events (in-hospital death or ICU transfer). The primary outcome was the composite of in-hospital death or ICU transfer. The association between critical illness events on the same ward across 6-hour intervals was studied using discrete-time survival analysis, adjusting for patient and situational factors. The association between critical illness events on different comparable wards in the same hospital was measured as a negative control. The cohort included 118 529 hospitalizations (median age, 72 years [IQR, 56-83 years]; 50.7% male). Death or ICU transfer occurred in 8785 hospitalizations (7.4%). Patients were more likely to experience the primary outcome after exposure to 1 prior event (adjusted odds ratio [AOR], 1.39; 95% CI, 1.30-1.48) and more than 1 prior event (AOR, 1.49; 95% CI, 1.33-1.68) in the prior 6-hour interval compared with no exposure. The exposure was associated with increased odds of subsequent ICU transfer (1 event: AOR, 1.67; 95% CI, 1.54-1.81; >1 event: AOR, 2.05; 95% CI, 1.79-2.36) but not death alone (1 event: AOR, 1.08; 95% CI, 0.97-1.19; >1 event: AOR, 0.88; 95% CI, 0.71-1.09). There was no significant association between critical illness events on different wards within the same hospital. Findings of this cohort study suggest that patients are more likely to be transferred to the ICU in the hours after another patient's critical illness event on the same ward. This phenomenon could have several explanations, including increased recognition of critical illness and preemptive ICU transfers, resource diversion to the first event, or fluctuations in ward or ICU capacity. Patient safety may be improved by better understanding the clustering of ICU transfers on medical wards.

An exploratory follow-up study of cannabis use and decision-making under various risk conditions within adolescence.

Studies examining the associations between decision-making (DM) and cannabis use (CU) often use cross-sectional, adult samples, and composite scores or single tasks to assess DM. The present study explored differential associations between tasks assessing DM under various risk conditions (i.e., ambiguous vs. explicit; gain vs. loss) and CU frequency, CU-related problems, and CU disorder (CUD) onset across a 2-year period within adolescence. Adolescents (n = 401, 90% Hispanic) aged 14-17 at baseline participated in five biannual assessments. CU frequency, CU-related problems, and CUD were assessed using the Drug Use History Questionnaire, Marijuana Problems Scale, and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, fourth edition, respectively. DM was assessed using the Iowa gambling task (IGT), Game of Dice Task (GDT), and Cups Task. We used latent growth curve modeling to examine bidirectional associations between DM and escalation in CU frequency and CU-related problems, and discrete time survival analyses to determine whether baseline performance across DM tasks predicted CUD onset. Baseline performance on the GDT predicted greater escalation in CU (β = .200, p = .008) and CU-related problems (β = .388, p = .035). No other significant associations were found. DM under explicit risk may be a more salient risk factor for escalating CU and CU-related problems than DM under ambiguous risk. Deficits in executive functioning could partially explain the results. Findings suggest that neurocognitive development should inform prevention and intervention efforts focused on reducing CU. Given the exploratory nature of the present study, replication of findings is needed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Individual Mobility across Clusters: The Impact of Ignoring Cross-Classified Data Structures in Discrete-Time Survival Analysis

A multilevel-discrete time survival model may be appropriate for purely hierarchical data, but when data are non-purely hierarchical due to individual mobility across clusters, a cross-classified discrete time survival model may be necessary. The purpose of this research was to investigate the performance of a cross-classified discrete-time survival model and assess the impact of ignoring a cross-classified data structure on the model parameters of a conventional discrete-time survival model and a multilevel discrete-time survival model. A Monte Carlo simulation was used to examine the performance of three discrete-time survival models when individuals are mobile across clusters. Simulation factors included the value of the between-clusters variance, number of clusters, within-cluster sample size, Weibull scale parameter, and mobility rate. The results suggest that substantial relative parameter bias, unacceptable coverage of the 95% confidence intervals, and severely biased standard errors are possible for all model parameters when a discrete-time survival model is used that ignores the cross-classified data structure. The findings presented in this study are useful for methodologists and practitioners in educational research, public health, and other social sciences where discrete-time survival analysis is a common methodological technique for analyzing event-history data.

Using remotely monitored patient activity patterns after hospital discharge to predict 30 day hospital readmission: a randomized trial

Hospital readmission prediction models often perform poorly, but most only use information collected until the time of hospital discharge. In this clinical trial, we randomly assigned 500 patients discharged from hospital to home to use either a smartphone or wearable device to collect and transmit remote patient monitoring (RPM) data on activity patterns after hospital discharge. Analyses were conducted at the patient-day level using discrete-time survival analysis. Each arm was split into training and testing folds. The training set used fivefold cross-validation and then final model results are from predictions on the test set. A standard model comprised data collected up to the time of discharge including demographics, comorbidities, hospital length of stay, and vitals prior to discharge. An enhanced model consisted of the standard model plus RPM data. Traditional parametric regression models (logit and lasso) were compared to nonparametric machine learning approaches (random forest, gradient boosting, and ensemble). The main outcome was hospital readmission or death within 30 days of discharge. Prediction of 30-day hospital readmission significantly improved when including remotely-monitored patient data on activity patterns after hospital discharge and using nonparametric machine learning approaches. Wearables slightly outperformed smartphones but both had good prediction of 30-day hospital-readmission.

Is the association between sexual minority status and suicide-related behaviours modified by rurality? A discrete-time survival analysis using longitudinal health administrative data

BackgroundWhile self-reported data shows that lesbian, gay, and bisexual (LBG) individuals have a greater suicide-related behaviours (SRB) risk, little is known about how rurality may amplify SRB risk associated with sexual minority status. Sexual minority individuals in rural areas may experience unique stressors due to stigma and a lack of LGB-specific social and mental health services. Using a population-representative sample linked to clinical SRB outcomes, we examined whether rurality modifies the association between sexual minority status and SRB risk. MethodsA nationally representative survey linked to administrative health data was used to construct a cohort of individuals (unweighted n = 169,091; weighted n = 8,778,115) in Ontario, Canada, and captured all SRB-related emergency department visits, hospitalizations, and deaths between 2007 and 2017. Sex-stratified discrete-time survival analyses were used to examine interactions between rurality and sexual minority status on SRB risk while controlling for potential confounders. ResultsSexual minority men had 2.18 times higher SRB odds compared to their heterosexual counterparts (95%CI 1.21–3.91), while sexual minority women had 2.07 times higher odds (95%CI 1.48–2.89) after adjusting for the confounders. The Rurality Index of Ontario and the Index of Remoteness were associated with the odds of SRB in a dose-response manner. No significant interactions were observed between rural and sexual minority status. ConclusionsOur study provides evidence that rural and sexual minority status both independently contribute to an elevated likelihood of SRB; however, rurality did not appear to modify SRB risk by sexual orientation. Implementation and evaluation of interventions to reduce SRB in both rural and sexual minority populations are required.

The association between cannabis use and risk of non-medical pain reliever misuse onset among young adults in a legal cannabis context

BackgroundLittle is known about the prospective relationship between cannabis use and pain reliever misuse. This study examined associations of non-medical and medical cannabis use with onset of non-medical pain reliever misuse among young adults in Washington State (WA), where non-medical cannabis is legal. MethodsData were from a cohort-sequential study of adults 18–25 residing in WA. Four annual surveys were used from cohorts recruited in 2014, 2015, and 2016. Participants who had not reported non-medical pain reliever misuse at baseline were included in discrete time survival analyses (N = 4,236). Odds ratios (ORs) were estimated for new onset of non-medical pain reliever misuse in any given follow-up year over the course of three years according to baseline non-medical and medical cannabis use. ResultsWhen included separately in models, non-medical and medical cannabis use at baseline were associated with increased risk of non-medical pain reliever misuse adjusting for demographic characteristics as well as past year cigarette use and alcohol use (non-medical OR = 5.27; 95 % CI: 3.28, 8.48; medical OR = 2.21; 95 % CI: 1.39, 3.52). Including both forms of use in the model, associations of non-medical and medical cannabis use with non-medical pain reliever misuse onset remained (non-medical OR = 4.64; 95 % CI: 2.88, 7.49; medical OR = 1.65; 95 % CI: 1.04, 2.62). ConclusionsDespite claims that cannabis use may reduce opioid use and related harms, findings suggest that cannabis use, including medical use, may not be protective, but instead may increase risk for non-medical pain reliever misuse.

Investigating suicide related behaviours across sexual orientation and neighbourhood deprivation levels: A cohort study using linked health administrative data.

There have been no studies examining how neighbourhood deprivation modifies the effects of sexual minority status on suicide-related behaviours (SRB). Sexual minority individuals in deprived areas may face unique challenges and stressors that exacerbate their risk of SRB. This study aims to investigate the association between sexual minority status and clinical SRB, and examine whether the effect of neighbourhood deprivation differs across sexual orientation. A population-representative survey sample (169,090 respondents weighted to represent 8,778,120 individuals; overall participation rate 75%) was linked to administrative health data in Ontario, Canada to measure SRB-related events (emergency department visits, hospitalizations, and deaths) from 2007 to 2017. Neighbourhood-level deprivation was measured using the Ontario Marginalisation index measure of material deprivation at the dissemination area level. Discrete-time survival analysis models, stratified by sex, tested the effects of neighbourhood deprivation and sexual minority status, while controlling for individual-level covariates. Sexual minority men had 2.79 times higher odds of SRB compared to their heterosexual counterparts (95% CI 1.66 to 4.71), while sexual minority women had 2.14 times higher odds (95% CI 1.54 to 2.98). Additionally, neighbourhood deprivation was associated with higher odds of SRB: men in the most deprived neighbourhoods (Q5) had 2.01 times higher odds (95% CI 1.38 to 2.92) of SRB compared to those in the least deprived (Q1), while women had 1.75 times higher odds (95% CI 1.28 to 2.40). No significant interactions were observed between sexual minority status and neighbourhood deprivation levels. In both men and women, sexual minority status and neighbourhood deprivation are independent risk factors for SRB. Despite the lack of effect modification, sexual minorities living in the most deprived neighbourhoods have the highest chances of SRB. Future investigations should evaluate interventions and policies to improve sexual minority mental health and address neighbourhood deprivation.