Prior Health Service Research Articles

Outcomes of a policy to prioritize populations with expected healthcare barriers for subsidized PrEP care in Amsterdam, the Netherlands: a cross-sectional study.

The Dutch HIV pre-exposure prophylaxis (PrEP) pilot provided subsidized PrEP care to maximum 2,900 individuals at a time in Amsterdam. Populations with expected barriers to accessing PrEP elsewhere were prioritized for program inclusion. We evaluated their prior sexual health service engagement and PrEP need. Cross-sectional analysis using enrolment data. We included individuals ever enrolled in the PrEP program at the Center for Sexual Health (CSH) Amsterdam between 2019-2023. We calculated the proportion belonging to higher-priority groups (i.e.,<25 years old, transgender, sex worker, uninsured or migrant). We defined classes of sexual health service engagement in the 12 months preceding enrolment using latent class analysis (LCA). We compared engagement classes, sexual behavior and positivity of HIV and sexually transmitted infections (STI) between higher- and lower-priority groups. 2,004/4,075 (49%) individuals enrolled belonged to higher-priority groups. LCA showed three classes of prior engagement: "Newly engaged" (14%,n = 551) were new to the CSH-Amsterdam; "PrEP initiators" (40%,n = 1,642) previously visited the CSH-Amsterdam but had not used PrEP; "PrEP experienced" individuals (46%,n = 1,882) previously accessed PrEP. Higher-priority groups were more often "newly engaged" or "PrEP-initiators" than "PrEP-experienced". Higher-priority groups less often had condomless anal sex with casual partners or chemsex in the prior six months. Positivity of bacterial STI was similar between higher-priority (n = 300/2,004, 15.0%) and lower-priority (n = 315/2,071, 15.2%) groups. 13/14 HIV diagnoses at enrolment were in higher-priority groups. Higher-priority populations had less often previously used sexual health services and accounted for most new HIV diagnoses at enrolment. Engaging these populations in sexual healthcare, including PrEP, should be stressed.

Youth cannabis use and subsequent health service use for mood and anxiety disorders: A population-based cohort study

Epidemiologic research suggests a modest association between youth cannabis use and mood and anxiety disorders (MADs). However, current evidence is based mostly on cohort studies using data from the 20th century when cannabis was significantly less potent than today. We linked population-based survey data from 2009 to 2012 with administrative records of health services covered under universal healthcare up to 2017. The cohort included youth aged 12 to 24 years at baseline living in Ontario, Canada with no prior MAD health service use (n = 8,252). We conducted a multivariable Cox model to estimate the association between cannabis use frequency (never, <weekly, weekly+) and MAD health service use (hospitalization, ED visit, or outpatient physician visit) in the following 3 years, adjusting for sociodemographic factors and other substance use. Compared to no cannabis use, <weekly use was significantly associated with subsequent MAD health service use (aHR=1.48; 95 % CI: 1.10–1.99) while weekly+ use was not (aHR=0.92; 95 % CI: 0.63–1.34). Sex and age interactions were not significant on the multiplicative or additive scales. This study found a modest longitudinal association between youth cannabis use and MAD health service use but no evidence of a linear dose-response relationship. Further research is needed to clarify these findings.

The effect of non-medical cannabis retailer proximity on use of mental health services for psychotic disorders in Ontario, Canada.

Cannabis is associated with the onset and persistence of psychotic disorders. Evidence suggests that accessibility of substances is associated with an increased risk of use-related harms. We sought to examine the effect of residing in proximity to non-medical cannabis retailers on the prevalence of health service use for psychosis. We conducted a cross-sectional study using linked health administrative data, and used geospatial analyses to determine whether people in Ontario, Canada (aged 14-60 years) resided within walking (1.6 km) or driving (5.0 km) distance of non-medical cannabis retailers (open as of February-2020). We identified outpatient visits, emergency department (ED) visits, and hospitalizations for psychotic disorders between 01-April-2019 and 17-March-2020. We used zero-inflated Poisson regression models and gamma generalized linear models to estimate the association between cannabis retailer proximity and indicators of health service use. Non-medical cannabis retailers were differentially located in areas with high levels of marginalization and pre-existing health service use for psychosis. People residing within walking or driving distance of a cannabis retailer had a higher rate of psychosis-related outpatient visits, ED visits, and hospitalizations, compared to people living outside these areas. This effect was stronger among those with no prior service use for psychosis. Proximity to a non-medical cannabis retailer was associated with higher health service use for psychosis, even after adjustment for prior health service use. These findings suggest that opening of non-medical cannabis retailers could worsen the burden of psychosis on mental health services in areas with high-risk populations.

Chronic Psychotic Disorders and Correctional Involvement: A Population-Based Matched Case-Control Study in Ontario, Canada.

Individuals with chronic psychotic disorders are overrepresented in correctional facilities, but little is known about factors that increase the risk of correctional involvement. The objective of this study was to compare individuals with chronic psychotic disorders who were released from correctional facilities in Ontario to individuals with chronic psychotic disorders but no correctional involvement on sociodemographic, clinical, and prior mental health-related health service utilization characteristics. All individuals with chronic psychotic disorders who were released from a provincial correctional facility in Ontario in 2010 were matched (1:2) by age and sex to Ontario residents with chronic psychotic disorders and no correctional involvement. Covariates included sociodemographic (rural residence, marginalization such as residential instability quintile, material deprivation quintile, dependency quintile, and ethnic concentration quintile) and clinical (duration of chronic psychotic disorder and comorbidities) characteristics, and mental health-related health service utilization characteristics (primary care physician, psychiatrist and emergency department visits, and hospitalizations) 1 and 3 years prior to correctional involvement. The association between correctional involvement and prior health service utilization was measured by estimating incidence rate ratios using Poisson and negative-binomial regressions. Individuals with correctional involvement (N = 3,197) lived in neighbourhoods with higher material deprivation and residential instability, and had a shorter duration of illness, and more psychosocial comorbidities (e.g., behavioural issues and depression) than individuals without correctional involvement (N = 6,393). Adjusting for sociodemographic and clinical variables, individuals with correctional involvement had a higher rate of mental health-related primary care physician visits, emergency department visits, and hospitalizations but a lower rate of psychiatrist visits prior to correctional involvement, compared to individuals without correctional involvement. Despite higher mental health-related comorbidities and higher rates of accessing acute mental health services among individuals with chronic psychotic disorders and correctional involvement, visits to psychiatrists prior to involvement were low.

Young people with prior health service contacts have increased risk of repeated alcohol-related harm hospitalisations

Young people with prior health service contacts have increased risk of repeated alcohol-related harm hospitalisations

Premature mortality in young people accessing early intervention youth mental healthcare: data-linkage cohort study

Understanding premature mortality risk from suicide and other causes in youth mental health cohorts is essential for delivering effective clinical interventions and secondary prevention strategies. To establish premature mortality risk in young people accessing early intervention mental health services and identify predictors of mortality. State-wide data registers of emergency departments, hospital admissions and mortality were linked to the Brain and Mind Research Register, a longitudinal cohort of 7081 young people accessing early intervention care, between 2008 and 2020. Outcomes were mortality rates and age-standardised mortality ratios (SMR). Cox regression was used to identify predictors of all-cause mortality and deaths due to suicide or accident. There were 60 deaths (male 63.3%) during the study period, 25 (42%) due to suicide, 19 (32%) from accident or injury and eight (13.3%) where cause was under investigation. All-cause SMR was 2.0 (95% CI 1.6-2.6) but higher for males (5.3, 95% CI 3.8-7.0). The mortality rate from suicide and accidental deaths was 101.56 per 100 000 person-years. Poisoning, whether intentional or accidental, was the single greatest primary cause of death (26.7%). Prior emergency department presentation for poisoning (hazard ratio (HR) 4.40, 95% CI 2.13-9.09) and psychiatric admission (HR 4.01, 95% CI 1.81-8.88) were the strongest predictors of mortality. Premature mortality in young people accessing early intervention mental health services is greatly increased relative to population. Prior health service use and method of self-harm are useful predictors of future mortality. Enhanced care pathways following emergency department presentations should not be limited to those reporting suicidal ideation or intent.

Exploring barriers and enablers of self-management behaviours in patients with diabetic foot ulcers: A qualitative study from the perceptions of patients, caregivers, and healthcare professionals in primary care.

Exploring barriers and enablers of self-management behaviours in patients with diabetic foot ulcers: A qualitative study from the perceptions of patients, caregivers, and healthcare professionals in primary care.

Health service use before and after dementia diagnosis: a retrospective matched case–control study

ObjectivesThis study investigated patterns in health service usage among older adults with dementia and matched controls over a 10-year span from 5 years before until 5 years after diagnosis.DesignPopulation-based retrospective...

Young people with prior health service contacts have increased risk of repeated alcohol-related harm hospitalisations.

After a first alcohol-related hospitalisation in youth, subsequent hospitalisations may demonstrate an increased risk of further alcohol-related hospitalisations, but there is no existing data on this. A retrospective longitudinal study between July 1992 and June 2017 using linked hospital administrative data identified 23 464 Western Australian young people [9009 (38.4%) females and 14 455 (61.6%) males], aged 12-24 years hospitalised for at least one alcohol-related harm (ARH) episode of care. Cox regression was used to estimate hazard ratios (HR) between risk factors and repeated alcohol-related hospitalisation after the first discharge for ARH. Of those admitted for an alcohol-related hospitalisation (n=23 464), 21% (n=4996) were readmitted for ARH. This high-risk sub-group comprised 46% (n=16 017) of the total alcohol-related admissions (n=34 485). After the first discharge for ARH, 16% (804) of people who experienced an alcohol-related readmission were readmitted within 1 month, and 51.8% (2589) were readmitted within 12 months. At increased risk of readmission were Aboriginal people and those with prior health service contacts occurring before their first alcohol-related hospitalisation, including illicit drug hospitalisations, mental health contacts and, in a sub-analysis, emergency department presentations. The probability of a repeated ARH hospitalisation was highest in the first month after initial discharge. There is a high-risk sub-group of young people more likely to have a repeat ARH hospitalisation. This represents an opportunity to provide interventions to those most at risk of repeated ARH.

Modifiable psychosocial risk factors and delayed onset of dementia in older populations: analysis of two prospective US cohorts

ObjectivePreventing Alzheimer’s dementia (AD) fundamentally equates to delaying onset. Thus, we quantified associations of modifiable, psychosocial risk factors to years of delayed onset of dementia.DesignTwo prospective cohorts (n=2860) with negative...

Factors associated with accessing long-term adult social care in people aged 75 and over: a retrospective cohort study.

BackgroundAn ageing population and limited resources have put strain on state provision of adult social care (ASC) in England. With social care needs predicted to double over the next 20 years, there is a need for new approaches to inform service planning and development, including through predictive models of demand.ObjectiveDescribe risk factors for long-term ASC in two inner London boroughs and develop a risk prediction model for long-term ASC.MethodsPseudonymised person-level data from an integrated care dataset were analysed. We used multivariable logistic regression to model associations of demographic factors, and baseline aspects of health status and health service use, with accessing long-term ASC over 12 months.ResultsThe cohort comprised 13,394 residents, aged ≥75 years with no prior history of ASC at baseline. Of these, 1.7% became ASC clients over 12 months. Residents were more likely to access ASC if they were older or living in areas with high socioeconomic deprivation. Those with preexisting mental health or neurological conditions, or more intense prior health service use during the baseline period, were also more likely to access ASC. A prognostic model derived from risk factors had limited predictive power.ConclusionsOur findings reinforce evidence on known risk factors for residents aged 75 or over, yet even with linked routinely collected health and social care data, it was not possible to make accurate predictions of long-term ASC use for individuals. We propose that a paradigm shift towards more relational, personalised approaches, is needed.

Personalized prediction of early childhood asthma persistence: A machine learning approach.

Early childhood asthma diagnosis is common; however, many children diagnosed before age 5 experience symptom resolution and it remains difficult to identify individuals whose symptoms will persist. Our objective was to develop machine learning models to identify which individuals diagnosed with asthma before age 5 continue to experience asthma-related visits. We curated a retrospective dataset for 9,934 children derived from electronic health record (EHR) data. We trained five machine learning models to differentiate individuals without subsequent asthma-related visits (transient diagnosis) from those with asthma-related visits between ages 5 and 10 (persistent diagnosis) given clinical information up to age 5 years. Based on average NPV-Specificity area (ANSA), all models performed significantly better than random chance, with XGBoost obtaining the best performance (0.43 mean ANSA). Feature importance analysis indicated age of last asthma diagnosis under 5 years, total number of asthma related visits, self-identified black race, allergic rhinitis, and eczema as important features. Although our models appear to perform well, a lack of prior models utilizing a large number of features to predict individual persistence makes direct comparison infeasible. However, feature importance analysis indicates our models are consistent with prior research indicating diagnosis age and prior health service utilization as important predictors of persistent asthma. We therefore find that machine learning models can predict which individuals will experience persistent asthma with good performance and may be useful to guide clinician and parental decisions regarding asthma counselling in early childhood.

Prevalence and Predictors of Reincarceration after Correctional Center Release: A Population-based Comparison of Individuals with and without Schizophrenia in Ontario, Canada: Prévalence et prédicteurs de la réincarcération après la libération d'un centre correctionnel : une comparaison dans la population-de personnes souffrant ou non de schizophrénie en Ontario, Canada.

Individuals with schizophrenia are overrepresented in correctional facilities relative to their population-based prevalence. The purpose of this study was to determine the rate and predictors of reincarceration of individuals with schizophrenia after release from correctional facilities. This was a retrospective cohort study that included all people released from Ontario's provincial correctional facilities from January 1 to December 31, 2010. Individuals with schizophrenia were identified using a population-based algorithm. The primary outcome was time to reincarceration. Covariates included sociodemographic characteristics (age, sex, neighborhood income quintile, urban/rural residence), health service utilization (primary care physician visits, psychiatrist visits, psychiatric and nonpsychiatric hospitalizations, emergency department visits), and other clinical comorbidity. Survival analysis was used to examine the association between schizophrenia and reincarceration. Among 46,928 individuals, N = 3,237 (7%) had a diagnosis of schizophrenia. Approximately 67.5% of these individuals were reincarcerated within 5 years following their first release in 2010, compared to 58.8% of individuals without schizophrenia. Individuals with schizophrenia were 40% (HR = 1.39, 95% CI, 1.33 to 1.45) more likely to be reincarcerated following release than the control group after adjusting for demographic characteristics. This association reduced to 8% (HR = 1.08, 95% CI,1.03 to 1.14) after adjusting for prior health service utilization, prior correctional involvement, and comorbidities. Individuals with schizophrenia were more likely to experience reincarceration after release from correctional facilities. This risk is partly explained by prior correctional involvement, health service utilization, and comorbidities. Future research should focus on risk factors predicting the higher reincarceration rate and interventions to reduce correctional involvement.

Despite Having Worse Risk Profiles, Northern Albertans Wait Longer for Specialist Follow-up After Emergency Department Visits for Atrial Fibrillation

BackgroundAtrial fibrillation and flutter (AFF) are common arrhythmias diagnosed in the emergency department (ED), and prompt follow-up with specialists may yield better outcomes. This study examines time to first specialist outpatient visit following ED discharge for AFF. MethodsAlberta residents aged ≥ 35 years with ED presentations for AFF ending in discharge during 2017-2018 were extracted and linked with hospitalizations and physician claims. A spatial scan and multinomial logistic regression were performed. Regression model predictors included demographics, prior diagnoses, and prior health service use. ResultsED presentations for 4387 patients (54% male; mean age 68 years) were analyzed. Two geographic areas were identified as clusters that had longer times than would be expected by chance: a north cluster of northern areas with an estimated median time of 98 days (95% confidence interval [CI] 82,139), and an east cluster of eastern areas with a median of 57 days (95% CI 47, 68). Patients in the north cluster were more likely to be younger (adjusted odds ratio [aOR] = 0.76 per 5 years, 95% CI 0.62, 0.93) and have prior histories of AFF (aOR = 1.45, 95% CI 1.11, 1.90), congestive heart failure (aOR=1.51, 95% CI 1.15, 1.98), chronic obstructive pulmonary disease (aOR = 2.03, 95% CI 1.55, 2.65), and diabetes (aOR = 1.30, 95% CI 1.00, 1.67). They were less likely to have prior general practitioner outpatient visits (aOR = 0.65 per 5 visits, 95% CI 0.53, 0.81) and specialist outpatient visits (aOR = 0.39, 95% CI 0.30, 0.50) than other patients. ConclusionsDespite being at higher risk, patients in northern areas took longer to see a specialist after an ED presentation for AFF than those from other regions. Innovative strategies for promoting specialist follow-up should be explored.

Surveillance studies involving HIV testing are needed: Will at-risk youth participate?

Adolescent males who have sex with males (AMSMs) account for high numbers of new HIV diagnoses. To date, surveillance data have been limited to diagnosed cases of HIV, resulting in an underestimation of risk and burden among AMSMs unwilling or unable to access HIV testing. This study identified facilitators and barriers to AMSMs' participation in future surveillance studies involving HIV testing. AMSMs (n = 198) aged 14 to 17 years participated. The majority identified as non-Hispanic White or Latinx, had a least 1 male sex partner, and self-reported HIV negative. Participants read an online survey beginning with a vignette describing a hypothetical HIV surveillance study requiring HIV testing. They then completed questions assessing likelihood to participate, perceived research benefits and risks, attitudes toward HIV risk, prior HIV health services, and parental awareness of sexual orientation. Approximately 40% indicated strong willingness to participate. Willingness was positively related to perceived HIV risk, free access to HIV testing, counseling and referral if testing positive, confidentiality protections, and lack of access to a trusted physician. Having to tell others if one tested positive for HIV and requirements for guardian permission were significant participation barriers. Inclusion of HIV testing in surveillance studies is essential for accurate estimation of HIV incidence and prevalence among AMSMs. Successful recruitment of sexual minority youth into sexual health surveillance research will require procedures tailored to youth's health care needs and concerns, including adequate HIV counseling, referral to treatment if seropositive, and attention to concerns regarding guardian permission. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The costs of traumatic head injury and associated factors at University of Gondar Specialized Referral Hospital, Northwest Ethiopia

BackgroundHead injuries account for 650,000 annual deaths worldwide. The cost for treating head injury was estimated at US $200 million annually. This contributes to economic impoverishment in low income countries like Ethiopia. Hence, this study was aimed to assess the cost of Traumatic Head Injury (THI) and associated factors in the University of Gondar Specialized Referral Hospital.MethodAn institution-based cross-sectional study was conducted from March 01 to May 30, 2017. A total of 387 THI patients were included in the study. An interviewer-administered questionnaire was used for data collection. Direct costs and indirect costs were measured by using the bottom-up approach. Data were entered into Epi-Info version 7 and imported to SPSS version 20 for analysis. Simple and multiple linear regression analysis were done to identify factors associated with cost of THI.ResultsThe mean cost of THI per patient was 4673.43 Ethiopian Birr (ETB), 95% CI (4523.6-4823.3), and length of hospital stay averaged 1.73, 95% CI (1.63–1.82). Direct non-medical cost, like transportation fee 1896.19 ETB (±762.56 SD) and medical costs 1101.66 ETB (±534.13 SD) were account for 40.57 and 23.58% of total costs respectively. The indirect cost, loss of income by patient and their attendant due to injury, was 1675.58 ETB (+ 459.26 SD). Patients with moderate and severe levels of injury have 635.167 ETB (Standardized coefficient = 0.173, p < 0.001) and 773.621 ETB (Standardized coefficient = 0. 132, p < 0.001) increased costs, respectively, compared to mild level THI patients. Costs for patients ages 31–45 years were 252.504 ETB (Standardized coefficient = − 0.066, p = 0.046) lower than costs for those 5–14 years old. The cost of THI patients increased by 1022.853 ETB for each additional day of hospital length of stay (Standardized coefficient = 0.648, p < 0.001).ConclusionMost expenses of the THI were from direct non-medical cost. Prior health service use, length of stay, level of injury, and age were significant predictors of cost of THI.

Association Between Prior Insurance and Health Service Utilization Among the Long-Term Uninsured in South Carolina.

Purpose: Strong evidence supports the relationship between health coverage and improved health status. Little is known about the lasting impact of prior health insurance on the prior insured's use of health services. We aimed to examine the association between prior insurance status and health service utilization (HSU) among the long-term uninsured (LTU) in South Carolina.Methods: The current study used data from in-person interviews of the LTU collected in a 2014 cross-sectional South Carolina survey. Men and women between 18–64 years of age who reported not having health insurance for at least 24 months at the time of data collection were included. Propensity score analysis was used to examine the associations between prior insurance status and three outcome variables: (1) having a usual source of care, (2) HSU, and (3) delaying health care needs.Results: Prior health insurance significantly predicted a greater likelihood of having a usual source of care (effect size: 9.2%, p=0.004) and having had at least one preventive visit during the past 2 years (effect size: 6.4%, p=0.035). Prior insurance coverage was positively associated with delayed health care utilization, but the result was not statistically significant (p=0.703).Conclusions: Among the LTU, ever having insurance coverage was positively associated with having a usual source of care and HSU. The lasting impact of insurance coverage on HSU behavior extends beyond the period of insurance coverage, which provides a more comprehensive and deeper understanding of the long-term implications of national and local efforts in expanding insurance coverage.

32. Receipt of Addiction Treatment Following Opioid-Related Overdose Among Medicaid-Enrolled Youth

Evidence-based guidelines recommend adolescents and young adults (“youth”) with opioid use disorder (OUD) receive treatment that includes medication. Non-fatal opioid overdose may be a critical touchpoint when youth with previously undiagnosed OUD can be drawn into treatment. Amidst rising overdose rates, the extent to which youth receive timely, evidence-based treatment after opioid overdose is unknown. This study’s objectives were to determine the proportion of youth who receive recommended treatment within 30 days following an opioid overdose, and examine predictors of treatment receipt. We conducted a retrospective cohort study using the Truven MarketScan-IBM Watson Health data, which includes all inpatient, emergency department, outpatient, and pharmacy claims of 4,039,260 Medicaid-enrolled youth aged 13-22 years from 16 de-identified US states during 2009-2015. We identified youth who had a non-fatal opioid-related overdose using ICD-9 codes. We examined “timely” receipt of addiction treatment (i.e., within 30 days after overdose), including receipt of behavioral health services alone compared with receipt of medication (buprenorphine, methadone, or naltrexone, either alone or in combination with behavioral health services) using billing codes. Using multivariable logistic regression, we identified differences in treatment receipt, adjusting for potential confounders, including age, sex, race/ethnicity, psychiatric comorbidity, substance use disorders, and comorbid pain conditions. The non-fatal opioid-related overdose rate was 45.6 per 100,000 person-years. Among 3,835 youth experiencing overdose, 58.8% were female (21% of whom were pregnant) and 65.9% were non-Hispanic white. Median age was 18 years (IQR [16, 20]). Characteristics associated with overdose were older age (≥18 years), female sex, pregnancy, non-Hispanic white race/ethnicity, depression, anxiety, attention deficit hyperactivity disorder, substance use disorder (OUD, alcohol, and other), or pain condition (p<0.001 for all). Overall, 1142 youth (31.3%) received any addiction treatment within 30 days after overdose; 1,075 (29.5%) received only behavioral health services, and 67 (1.8%) received medication. Younger adolescents were less likely to receive medication (age 13-15: 0.5%; 16-17: 0.8%; 18-20: 1.8%; 21-22: 4.2%, p<0.001), though were more likely to receive any timely addiction treatment (age 13-15: adjusted odds ratio 1.66 [95% confidence interval 1.23-2.23]; age 16-17: 1.6 [1.22-2.09]) due to higher rates of behavioral health services. Youth who were engaged in treatment prior to overdose were more likely to continue the same treatment after overdose than individuals not previously in treatment (prior behavioral health: 5.66 [4.67-6.86]; prior medication treatment: 13.95 [7.32-26.61]), though were no more or less likely to receive the other modality of treatment after overdose. Many youth previously engaged in treatment did not resume treatment within 30 days of overdose (prior behavioral health services: 33.9%; prior medication: 40.2%). In this large study of youth experiencing opioid-related overdose, less than one-third received timely addiction treatment, and only 1 in 54 youth received recommended evidence-based medications. Even youth previously engaged in treatment had low rates of treatment after overdose. Interventions are urgently needed to link youth to treatment after overdose, with a priority placed on improving access to recommended medication treatment.

Analysing complex linked administrative data in health services research: Issues and solutions

IntroductionLinked administrative data are increasingly being used to evaluate the impact of health policy on health-service use/cost because they can comprehensively capture whole of population interactions with the health system. These analyses are complex comprising unbalanced panels and are at risk of endogeneity and associated problems.&#x0D; Objectives and ApproachWe evaluated the impact of changes in regularity of general practitioner contact on diabetes related hospitalisation before and after care coordination policies using whole of population, person-level linked primary care, hospital, Electoral Roll and death records. Complex panel random-effects modelling techniques were required due to the unbalanced structure of the data (individuals could exit and re-enter the study repeatedly), over-dispersion and high proportion of zeros, changes in availability of tests (ascertainment bias), the likelihood of prior health service use influencing the dependent variable (initial conditions and simultaneity/reverse causality bias) and likely correlation of observed and unobserved variables.&#x0D; ResultsMultivariable zero-inflated negative binomial and Cragg-hurdle clustered robust regression, which include separate components to model zero and non-zero outcomes, were required for these data. Mundlak variables (group-means of time-varying variables) were used to relax the assumption in the random-effects estimator that the observed variables were uncorrelated with the unobserved ones. Prior health service use was adjusted for using 4-year lags of GP contact and one-year lag of hospitalisation. The initial value of the dependent variable resolved the “initial condition” problem. Ascertainment bias was addressed using the number of years available for identification for each person as a covariate. AIC/BIC values were used to identify the best model. We found that more regular GP contact was associated with fewer hospitalisations, however this attenuated over time.&#x0D; Conclusion/ImplicationsAvailability of linked data, together with increases in computing power, has vastly increased its potential for use. This has also increased the complexity of analyses being undertaken necessitating recognizing and addressing problems, such as endogeneity, that arise due to the observational nature of the studies undertaken.

Untreated Sleep Apnea: An Analysis of Administrative Data to Identify Risk Factors for Early Nonadherence.

Discontinuation of positive airway pressure (PAP) treatment for obstructive sleep apnea (OSA) is widely reported, but research has not adequately addressed nonadherence with diagnostic testing for sleep disorders and initiation of PAP. This study sought to identify drivers of nonadherence with diagnostic sleep testing and PAP treatment initiation among patients preauthorized for these services. This observational cohort study used preauthorization records from a sleep management program and administrative medical claims from a large commercial health insurer. Participants included adults preauthorized for sleep testing and a subset in whom OSA was diagnosed and who were preauthorized for PAP treatment. Outcome measures were nonadherence with diagnostic sleep testing and PAP treatment initiation, identified as lack of a claim for a preauthorized service within 3 months of preauthorization of that service. Risk factors for nonadherence included patient demographics, prescribing factors, signs and symptoms of OSA, comorbidities, and prior health service utilization. Of 51,749 patients preauthorized for diagnostic testing, 23.5% did not undergo testing. Among 19,968 patients preauthorized for PAP treatment, 11.1% did not initiate treatment. Testing and treatment ordered by primary care providers, residence outside the Midwest region, and two or fewer office visits within 6 months before preauthorization were strong predictors of nonadherence. Apnea-hypopnea index score < 30 events/h was also a strong predictor of nonadherence with treatment initiation. This study adds to existing knowledge about risk factors for nonadherence with sleep testing and treatment initiation following preauthorization. Health plans and providers should develop strategies to better engage patients with higher risk of nonadherence.