Prevalent Cohort Research Articles

Determining sample sizes for combined incident and prevalent cohort studies with and without follow-up

Determining sample sizes for combined incident and prevalent cohort studies with and without follow-up

Doubly robust estimation under covariate-induced dependent left truncation

Summary In prevalent cohort studies with follow-up, the time-to-event outcome is subject to left truncation leading to selection bias. For estimation of the distribution of the time to event, conventional methods adjusting for left truncation tend to rely on the quasi-independence assumption that the truncation time and the event time are independent on the observed region. This assumption is violated when there is dependence between the truncation time and the event time, possibly induced by measured covariates. Inverse probability of truncation weighting can be used in this case, but it is sensitive to misspecification of the truncation model. In this work, we apply semiparametric theory to find the efficient influence curve of the expectation of an arbitrarily transformed survival time in the presence of covariate-induced dependent left truncation. We then use it to construct estimators that are shown to enjoy double-robustness properties. Our work represents the first attempt to construct doubly robust estimators in the presence of left truncation, which does not fall under the established framework of coarsened data where doubly robust approaches were developed. We provide technical conditions for the asymptotic properties that appear to not have been carefully examined in the literature for time-to-event data, and study the estimators via extensive simulation. We apply the estimators to two datasets from practice, with different right-censoring patterns.

Multimorbidity in Psoriasis as a Risk Factor for Psoriatic Arthritis: A Population-Based Study.

To examine multimorbidity in psoriasis and its association with the development of PsA. A retrospective cohort study was performed using the Rochester Epidemiology Project. Population-based incidence (2000-2009) and prevalence (Jan 1, 2010) cohorts of psoriasis were identified by manual chart review. A cohort of individuals without psoriasis (comparators) were identified (1:1 matched on age, sex, and county). Morbidities were defined using ≥2 Clinical Classification Software codes ≥30 days apart within prior five years. PsA was defined using ClASsification of Psoriatic ARthritis (CASPAR) criteria. χ2 and rank-sum tests were used to compare morbidities, and age-, sex-, and race-adjusted Cox models to examine the association of baseline morbidities in psoriasis with development of PsA. Among 817 incident psoriasis patients, the mean age was 45.2 years with 52.0% females, and 82.0% moderate/severe psoriasis. No multimorbidity differences were found between incident psoriasis patients and comparators. However, in the 1,088 prevalent psoriasis patients, multimorbidity was significantly more common compared with 1,086 comparators (OR : 1.35 and OR : 1.48 for ≥2 and ≥5 morbidities, respectively). Over a median 13.3-year follow-up, 23 patients (cumulative incidence: 2.9% by 15 years) developed PsA. Multimorbidity (≥2 morbidities) was associated with a 3-fold higher risk of developing PsA. Multimorbidity was more common in the prevalent but not incident cohort of psoriasis compared with the general population, suggesting patients with psoriasis may experience accelerated development of multimorbidity. Moreover, multimorbidity at psoriasis onset significantly increased the risk of developing PsA, highlighting the importance of monitoring multimorbid psoriasis patients for the development of PsA.

Association between proton pump inhibitors use and risk of asthma in Korea: A prevalent new-user cohort study.

There have been conflicting mechanisms that proton pump inhibitors (PPIs) may promote or prevent asthma development. However, the evidence on the association of PPI use with the risk of asthma and its exposure-response relationship has been limited. We aim to identify the association between the use of PPIs and the incidence of asthma, compared with use of histamine 2 receptor antagonists (H2RAs). A nationwide, prevalent new-user cohort study was conducted using Korea's National Sample Cohort database. Patients were defined as PPI or H2RA users between 2003 and 2019. PPI users matched to H2RA users based on time-conditional propensity score. Cox proportional hazards model was used to estimate adjusted hazard ratios with 95% confidence intervals of incident asthma associated with PPI use by duration of use, cumulative dose, and average dose per duration. Among the 250,041 pairs, PPI users (51.3% male; mean [SD] age, 42.6 [16.5]; mean follow-up, 6.7 years) showed a higher incidence rate of asthma (7.94 events per 1000 person-year) compared to H2RA users (3.70 events per 1000 person-year) with adjusted hazard ratio of 2.15 (95% confidence interval = 2.08-2.21). The risk of asthma was significantly increased across all observed groups of duration of use, cumulative dose, and average dose per duration. This study suggested that PPI use is associated with an increased risk of developing asthma compared to H2RA use.

Characteristics of Users and New Initiators of Single- and Multiple-Inhaler Triple Therapy for Chronic Obstructive Pulmonary Disease in Germany.

To assess patient characteristics of users and new initiators of triple therapy for chronic obstructive pulmonary disease (COPD) in Germany. Retrospective cohort study of patients with COPD and ≥1 prescription for single-inhaler triple therapy (SITT; fluticasone furoate/umeclidinium/vilanterol [FF/UMEC/VI] or beclomethasone dipropionate/glycopyrronium bromide/formoterol [BDP/GLY/FOR]) or multiple-inhaler triple therapy (MITT), using data from the AOK PLUS German sickness fund (1 January 2015-31 December 2019). The index date was the first date of prescription for FF/UMEC/VI or BDP/GLY/FOR (SITT users), or the first date of overlap of inhaled corticosteroid, long-acting β2-agonist, and long-acting muscarinic antagonist (MITT users). Two cohorts were defined: the prevalent cohort included all identified triple therapy users; the incident cohort included patients newly initiating triple therapy for the first time (no prior use of MITT or SITT in the last 2 years). Patient characteristics and treatment patterns were assessed on the index date and during the 24-month pre-index period. In total, 18,630 patients were identified as prevalent triple therapy users (MITT: 17,945; FF/UMEC/VI: 700; BDP/GLY/FOR: 908; non-mutually exclusive) and 2932 patients were identified as incident triple therapy initiators (MITT: 2246; FF/UMEC/VI: 311; BDP/GLY/FOR: 395; non-mutually exclusive). For both the prevalent and incident cohorts, more than two-thirds of patients experienced ≥1 moderate/severe exacerbation in the preceding 24 months; in both cohorts more BDP/GLY/FOR users experienced ≥1 moderate/severe exacerbation, compared with FF/UMEC/VI and MITT users. Overall, 97.9% of prevalent triple therapy users and 86.4% of incident triple therapy initiators received maintenance treatment in the 24-month pre-index period. In a real-world setting in Germany, triple therapy was most frequently used after maintenance therapy in patients with recent exacerbations, in line with current treatment recommendations.

Capturing Patient Value in an Economic Evaluation.

Economic evaluations predominantly use generic outcomes, such as the Euro Quality of Life-5 Dimension (EQ-5D), to assess health status. However, because of the generic nature, they are less suitable to capture the quality of life of patients with specific conditions. Given the transition to patient-centered (remote) care delivery, this study aims to evaluate the possibility of using disease-specific measures in a cost-effectiveness analysis. A real-life cohort from Maasstad Hospital (2020-2021) in the Netherlands, with 772 patients with rheumatoid arthritis (RA), was used to assess the cost-effectiveness of electronic consultations (e-consultations) compared with face-to-face consultations. The Incremental Cost-Effectiveness Ratio (ICER), based on the generic EQ-5D, was compared with ICER's based on RA-specific measures: the Rheumatoid Arthritis Impact of Disease (RAID) and Health Assessment Questionnaire-Disability Index (HAQ-DI). To compare the cost-effectiveness of these different measures, HAQ-DI and RAID were expressed in quality-adjusted life-years (QALYs) via estimated conversion equations. Disease-specific patient-reported outcome measures (PROMs) offer a promising alternative for traditional measures in economic evaluations, capturing patient-relevant domains more comprehensively. Because PROMs are increasingly applied in clinical practice, the next step entails modeling of an RA patient-wide conversion equation to implement PROMs in economic evaluations. The conventional ICER (eg, EQ-5D) indicates that e-consultations are cost-effective with cost savings of -€161,000 per QALY gained for a prevalent RA cohort treated in a secondary trainee hospital. RA-specific measures show similar results, with ICERs of -€163,000 per HAQ-DI (QALY) and -€223,000 per RAID (QALY) gained. RA-specific measures capture patient-relevant domains and offer the opportunity to improve the assessment and treatment of the disease impact.

PP103 Budget Impact Analysis Of Utilization Of WavelinQ Endo-arteriovenous Fistula System For Hemodialysis Patients: An Australian Hospital Perspective

IntroductionA high proportion of patients with end-stage kidney disease (ESKD) are treated with hemodialysis (HD). To lower morbidity and maintain overall cost control in patients with ESKD, it is crucial for health systems to establish and maintain durable hemodialysis (HD) access. Our objective was to assess the budget impact of utilizing the ‘WavelinQ Endo Arteriovenous Fistula (AVF) system’ (WavelinQ) for HD patients.MethodsA one-year economic model from the Hospital (Flinders Medical Centre, FMC) perspective was developed with Australian epidemiological and costing data. Clinical data were collected from real-world sources. The incident (n=50) and prevalent (n=250) cohorts were based on FMC utilization patterns. The current standard of care was surgical AVF (sAVF) and/or central venous catheters (CVC). With introduction of WavelinQ into practice, the substitution rate was set at 50 percent in new patients and ten percent amongst existing patients. Index procedure and reinterventions costs for the patient were based on the weighted average cost using National Efficient Price Determination 2020 to 21. Total costs preWavelinQ introduction were compared to post WavelinQ substitution to determine the budget impact.ResultsBased on FMC expected patient cohort and WavelinQ substitution rates, the mean annual cost savings per incident and prevalent patient were AUD26,873 and AUD3,549, respectively, which lead to overall mean annual cost savings per patient of AUD7,437. The calculated per patient additional upfront cost of AUD7,010 with the WavelinQ index procedure versus sAVF was more than offset by the savings due to less post-procedure reinterventions. Overall, at the assumed substitution rates with WavelinQ, the model predicted a cost saving of approximately AUD2.2 million dollars for FMC.ConclusionsThe use of WavelinQ is expected to lead to cost savings of AUD2.2 million dollars from the FMC perspective. Hospitals should consider not just the increase in upfront costs but also potential savings from less reintervention procedures. There is a need for continued research on the budget impact of different HD modalities across multiple settings.

Multimorbidity in systemic lupus erythematosus in a population-based cohort: the Lupus Midwest Network.

The objectives of this study were to assess the prevalence and incidence of multimorbidity and its association with the SLICC/ACR damage index (SDI) among patients with SLE. Using prevalent and incident population-based cohorts of patients with SLE and their matched comparators, we assessed 57 chronic conditions. Chronic conditions were categorized as SDI-related or SDI-unrelated. Multimorbidity was defined as the presence of two or more chronic conditions. The prevalence of multimorbidity for both cohorts was compared using logistic regression. Cox models were used to examine the development of multimorbidity after SLE incidence. The prevalent cohort included 449 patients with established SLE on 1 January 2015. They were three times more likely to have multimorbidity compared with non-SLE comparators [odds ratio (OR) 2.98, 95% CI 2.18-4.11]. The incident cohort included 270 patients with new-onset SLE. At SLE incidence, patients with SLE were more likely to have multimorbidity than comparators (OR 2.27, 95% CI 1.59-3.27). After incidence, the risk of developing multimorbidity was 2-fold higher among patients with SLE than among comparators [hazard ratio (HR) 2.11, 95% CI 1.59-2.80]. The development of multimorbidity was higher in patients with SLE based on SDI-related conditions (HR 2.91, 95% CI 2.17-3.88) than on SDI-unrelated conditions (HR 1.73, 95% CI, 1.32-2.26). Patients with SLE had a higher burden of multimorbidity, even before the onset of the disease. The risk disparity continued after SLE classification and was also seen in a prevalent SLE cohort. Multimorbidity was driven both by SDI-related and unrelated conditions.

Exploring the relationship between baseline health-related quality of life (AQoL-4D utility values) and mortality during long-term follow-up for people living with a psychotic disorder

Holistic summary measures of health-related quality of life (HRQoL) could provide useful information for screening and/or monitoring high-risk individuals. This study explores the association of baseline HRQoL (AQoL-4D values) with death from natural and external causes (such as suicide, overdose, or accident) in a prevalent cohort over a mean follow-up of 6.9-years. Baseline data were obtained from the 2010 National Survey of High Impact Psychosis (SHIP) and its 2012 sister survey, the North-Metro Survey of High Impact Psychosis. Follow-up data were obtained from the National Deaths Index (to January 18, 2018). Associations between baseline HRQoL (and the 12 individual items of the AQoL-4D) and deaths by cause, stratified by sex were investigated using multivariable Cox Proportional Hazards models, with age used as the time scale. Overall, 7.6 % of the cohort (137 of 1805 people meeting ICD-10 criteria for a psychotic disorder and agreeing to linkage) died, 4.2 % from natural causes (primarily heart disease and cancer) and 3.4 % from external causes. There was an association between low HRQoL (AQoL-4D ≤ 0.20) and mortality due to natural causes, primarily driven by difficulties with mobility and vision in men, and difficulty with household tasks in women. No significant associations were obtained between AQoL-4D utilities and death from external causes. Sleep problems were associated with death from external causes for men only. As people with psychotic disorders experience multiple causes of death with complex associations which are difficult to quantify, monitoring for low HRQoL using the AQoL-4D could be a useful indicator of increased mortality risk in this population. TwitterMonitoring for low HRQoL (AQoL-4D ≤ 0.20) could be a useful indicator of increased mortality risk from natural causes in people living with psychotic disorders, with differing but specific items of relevance to men and women.

10-year trends in oral anticoagulation therapies and ischemic stroke among 157,583 patients with non-valvular atrial fibrillation

Abstract Purpose Initiation of oral anticoagulation therapy (OAC) for stroke prevention in patients with atrial fibrillation (AF) is often suboptimal in clinical practice. We aimed to describe trends in OAC uptake and incidence of ischemic stroke over the past decade. Methods We retrospectively analyzed consecutive patients with non-valvular (NV) AF between January 2012 and July 2022 from 16 public hospitals. Annual incidence of AF was the number of new AF cases as proportion of adult population reported by Census and Statistics Department. Prescription of OAC (vitamin K antagonist (VKA) and direct oral anticoagulants (DOAC)) were recorded. OAC uptake was defined as initiation of OAC within 12 months from AF diagnosis. Incidence of ischemic stroke was calculated for both incident and prevalent AF cohorts over time. Logistic regression was conducted to identify predictors of OAC uptake. Results 157,583 NVAF patients (mean age 76.6±12.5 and female 49.6%) with mean CHA2DS2VASC 2.6±1.3 were identified. Between 2012 and 2022, incidence of new AF was steady across the years with mean of 0.19%±0.03% (range 0.16% to 0.24%) per year. OAC prescription increased from 15.3% to 46.0% and the incidence of ischemic stroke decreased significantly from 4.0% to 0.6% over the last decade (both p for trend <0.01). DOAC use increased steadily from 6.2% to 41.0% whereas VKA decreased from 9.1% to 3.5% (Figure). Mean time from AF diagnosis to OAC prescription was 0.6±1.6 months. Of all patients prescribed OAC, 40.8% initiated OAC within 1 month after AF diagnosis. CHA2DS2VASC scores ≥4 was associated with higher likelihood of OAC uptake (OR=1.74 (95%CI: 1.69-1.78). Conclusion Our real-world data demonstrated steady incidence of new NVAF diagnosis with increasing trend in OAC prescription, predominantly DOAC and decreasing incidence ischemic stroke over the last decade. However, overall utilization of OAC for stroke prevention remains suboptimal.

Nontuberculous mycobacterial (NTM) infections in bronchiectasis patients: A retrospective US registry cohort study

RationaleLongitudinal epidemiological and clinical data are needed to improve the management of patients with bronchiectasis developing nontuberculous mycobacterial (NTM) pulmonary disease. ObjectivesTo describe the epidemiology, patient management, and treatment outcomes of NTM infections in patients with bronchiectasis enrolled in the United States Bronchiectasis and NTM Research Registry (US BRR). MethodsThis was a retrospective cohort study of patients with bronchiectasis and NTM infections enrolled with follow-up in the US BRR in 2008–2019. The study included patients with ≥1 positive NTM respiratory culture in the 24-month baseline period (baseline NTM cohort) and/or during the annual follow-up visits (incident NTM cohort). Incidence, prevalence, baseline patient characteristics, treatment exposure, treatment outcomes, and respiratory clinical outcomes were described in the baseline NTM cohort, incident NTM cohort, and both cohorts combined (prevalent NTM cohort). ResultsBetween 2008 and 2019, 37.9% (1457/3840) of patients with bronchiectasis in the US BRR met the inclusion criteria for this study and were reported to have Mycobacterium avium complex (MAC) and/or Mycobacterium abscessus complex (MABSC) infections. MAC prevalence increased steadily in the US BRR during 2009–2019; incidence was relatively stable, except for a peak in 2011 followed by a slow decrease. MABSC and mixed MAC/MABSC infections were rare. Most patients with bronchiectasis and NTM infections in the registry were female, White, and aged >65 years. The antibiotics administered most commonly reflected current guidelines. In the prevalent cohort, 44.9% of MAC infections and 37.1% of MABSC infections remained untreated during follow-up, and MAC treatment was initiated with delay (>90 days after positive NTM respiratory culture) twice as frequently as promptly (≤90 days after positive NTM respiratory culture) (68.6% vs 31.4%, respectively). The median time from diagnosis to treatment was shorter for MABSC versus MAC infections (194.0 days [interquartile range (IQR) 8.0, 380.0] vs 296.0 days [IQR 35.0, 705.0], respectively). Among patients with MAC infections who completed treatment, 27.6% were classified as cured and 29.6% as treatment failure during the annual follow-up visit window. For MABSC, these proportions were 25.0% and 28.0%, respectively. ConclusionsA considerable proportion of MAC and MABSC infections were untreated or treated after initial delay/observation. MABSC infections were more likely to be treated and start treatment sooner than MAC infections. Further longitudinal studies are warranted to evaluate the monitor-with-delay approach and inform clinical guidelines.

Epidemiology and healthcare utilization of First Nations peoples living with spinal cord injury in Alberta: an observational study to explore health inequities

Study designRetrospective observational cohort study.ObjectivesEstimate spinal cord injury (SCI) prevalence in First Nations and non-First Nations populations and compare healthcare utilization as an indirect marker of health inequities.SettingAlberta, Canada.MethodsWe created a prevalent adult SCI cohort by identifying cases between April 1, 2002 and December 31, 2017 who were followed for common SCI complications and location of healthcare access from January 1, 2018 to December 31, 2019 using administrative data sources housed within Alberta Health Services (AHS). First Nations and non-First Nations SCI cohorts were divided into SCI etiology: traumatic SCI (TSCI) and non-traumatic SCI (NTSCI). Statistical analyses compared prevalence, demographics, healthcare utilization, and SCI complication rates. A secondary analysis was performed using case matching for demographics, injury type, injury level, and comorbidities.ResultsTSCI prevalence: 248 and 117 per 100,000 in First Nations and non-First Nations cohorts, respectively. NTSCI prevalence: 74 and 50 per 100,000 in First Nations and non-First Nations cohorts, respectively. Visit rates were higher in the TSCI First Nations cohort for visits to General Practitioner (GP), Emergency Department (ED), inpatient visits, and inpatient days with higher complication rates due to pulmonary, genitourinary, skin, and ‘other’ causes after case matching. Visits rates were higher in the NTSCI First Nations cohort for GP and specialists without differences in complication types after case matching.ConclusionsSignificant differences exist between First Nations and non-First Nations cohorts living with SCI in Alberta, suggesting healthcare inequities against First Nations Peoples in this province.

Familial hypercholesterolaemia in UK primary care: a Clinical Practice Research Datalink study of an under-recognised condition.

Studies utilising genotyping methods report the prevalence of familial hypercholesterolaemia to be as high as one in 137 of the adult population. To estimate the prevalence of familial hypercholesterolaemia measured by clinically coded diagnosis, associated treatments, and lipid measurements observed in UK primary care. This was a retrospective analysis using the Clinical Practice Research Datalink (CPRD) GOLD database. Patients aged ≥18 years and actively registered on the index date (30 June 2018) formed the study cohort. Point prevalence of familial hypercholesterolaemia for 2018 was estimated overall and for each nation of the UK. Patients with familial hypercholesterolaemia were stratified into primary and secondary prevention groups, defined as those with/without a prior diagnosis of atherosclerotic cardiovascular disease. Prevalence estimates and extrapolations were replicated for these subgroups. Baseline demographic, lipid, and clinical characteristics for the prevalent cohort were presented. In total, 4048 patients with familial hypercholesterolaemia formed the study cohort. The estimated familial hypercholesterolaemia prevalence for the UK was 16.4 per 10 000 (95% confidence interval [CI] = 16.0 to 16.9). Of these, 2646 (65.4%) patients with familial hypercholesterolaemia had a recent prescription for lipid-lowering therapy. Mean lipid levels were lower for those treated with lipid-lowering therapy compared with those untreated: 5.34 mmol/L (SD 1.50) versus 6.25 mmol/L (SD 1.55) for total cholesterol and 3.15 mmol/L (SD 1.34) versus 3.96 mmol/L (SD 1.36) for low-level density lipoprotein cholesterol. The estimated prevalence of familial hypercholesterolaemia was one in 608 of the population, less than expected from other studies, which may indicate that familial hypercholesterolaemia is under-recognised in UK primary care. Over one-third of diagnosed patients were undertreated and many did not achieve target goals, placing them at risk of cardiovascular events.

JAK-inhibitors and risk on serious viral infection, venous thromboembolism and cardiac events in patients with rheumatoid arthritis: A protocol for a prevalent new-user cohort study using the Danish nationwide DANBIO register.

Janus Kinase inhibitors (JAKis) are targeted synthetic disease-modifying antirheumatic drugs and represent an important alternative to treat patients with moderate to high rheumatoid arthritis (RA) disease activity. Safety concerns associated with increased risk for venous thromboembolism (VTE), serious viral infection, and, more recently, major adverse cardiovascular events (MACE) in JAKi users have emerged worldwide. However, as the exact mechanisms to explain these safety concerns remain unclear, the increased risk of VTE, MACE, and serious viral infection in JAKi users is heavily debated. In light of the need to enrich the safety profile of JAKis in real-world data, we aim to quantify the incidence and risk of MACE, VTE, and serious viral infections in RA patients registered in the Danish DANBIO registry, a nationwide registry of biological therapies used in rheumatology. Therefore, we will conduct a population-based cohort study using a prevalent new-user design. We will identify all RA patients in the DANBIO, ≥ 18 years old, receiving a JAKi or a tumor necrosis factor α inhibitor (TNF-αi) from January 2017 to December 2022. Prevalent and new users of JAKis will be matched to TNF-αi comparators with similar exposure history using time-conditional propensity scores (TCPS). We will describe the cumulative incidence of the outcomes (VTE, MACE, serious viral infection) in each exposure group (JAKi users; TNF-αi users), stratified by outcome type. Additionally, the Aalen-Johansen method will be used to estimate the time-to-event survival function stratified by outcome type. We will also estimate the hazard ratio (HR) with 95% confidence interval (CI) of each outcome in both exposure groups using the time-dependent Cox proportional hazards model. Results will enrich the safety profile of JAKis in real-world data.

Genetic Abnormalities in Extramedullary Multiple Myeloma.

Extramedullary multiple myeloma (or extramedullary disease, EMD) is an aggressive form of multiple myeloma (MM) that occurs when malignant plasma cells become independent of the bone marrow microenvironment. This may occur alongside MM diagnosis or in later stages of relapse and confers an extremely poor prognosis. In the era of novel agents and anti-myeloma therapies, the incidence of EMD is increasing, making this a more prevalent and challenging cohort of patients. Therefore, understanding the underlying mechanisms of bone marrow escape and EMD driver events is increasingly urgent. The role of genomics in MM has been studied extensively; however, much less is known about the genetic background of EMD. Recently there has been an increased focus on driver events for the establishment of distant EMD sites. Generally, high-risk cytogenetic abnormalities and gene signatures are associated with EMD, alongside mutations in RAS signalling pathways. More recently, changes in epigenetic regulation have also been documented, specifically the hypermethylation of DNA promoter regions. Therefore, the focus of this review is to summarize and discuss what is currently known about the genetic background of EMD in MM.

Estimation for the Cox model with biased sampling data via risk set sampling

Prevalent cohort sampling is commonly used to study the natural history of a disease when the disease is rare or it usually takes a long time to observe the failure event. It is known, however, that the collected sample in this situation is not representative of the target population which in turn leads to biased sample risk sets. In addition, when survival times are subject to censoring, the censoring mechanism is informative. In this paper, I propose a pseudo-partial likelihood estimation method for estimating parameters in the Cox proportional hazards model with right-censored and biased sampling data by adjusting sample risk sets. I study the asymptotic properties of the resulting estimator and conduct a simulation study to illustrate the finite sample performance of the proposed method. I also use the proposed method to analyze a set of HIV/AIDS data.

Evaluation of the natural history of disease by combining incident and prevalent cohorts: application to the Nun Study.

The Nun study is a well-known longitudinal epidemiology study of aging and dementia that recruited elderly nuns who were not yet diagnosed with dementia (i.e., incident cohort) and who had dementia prior to entry (i.e., prevalent cohort). In such a natural history of disease study, multistate modeling of the combined data from both incident and prevalent cohorts is desirable to improve the efficiency of inference. While important, the multistate modeling approaches for the combined data have been scarcely used in practice because prevalent samples do not provide the exact date of disease onset and do not represent the target population due to left-truncation. In this paper, we demonstrate how to adequately combine both incident and prevalent cohorts to examine risk factors for every possible transition in studying the natural history of dementia. We adapt a four-state nonhomogeneous Markov model to characterize all transitions between different clinical stages, including plausible reversible transitions. The estimating procedure using the combined data leads to efficiency gains for every transition compared to those from the incident cohort data only.

Equity of Cancer and Diabetes Co-Occurrence: A National Study With 44 Million Person-Years of Follow-Up

The co-occurrence of diabetes and cancer is becoming increasingly common, and this is likely to compound existing inequities in outcomes from both conditions within populations. In this study, we investigate the co-occurrence of cancer and diabetes by ethnic groups in New Zealand. National-level diabetes and cancer data on nearly five million individuals over 44 million person-years were used to describe the rate of cancer in a national prevalent cohort of peoples with diabetes versus those without diabetes, by ethnic group (Māori, Pacific, South Asian, Other Asian, and European peoples). The rate of cancer was greater for those with diabetes regardless of ethnic group (age-adjusted rate ratios, Māori, 1.37; 95% CI, 1.33 to 1.42; Pacific, 1.35; 95% CI, 1.28 to 1.43; South Asian, 1.23; 95% CI, 1.12 to 1.36; Other Asian, 1.31; 95% CI, 1.21 to 1.43; European, 1.29; 95% CI, 1.27 to 1.31). Māori had the highest rate of diabetes and cancer co-occurrence. Rates of GI, endocrine, and obesity-related cancers comprised a bulk of the excess cancers occurring among Māori and Pacific peoples with diabetes. Our observations reinforce the need for the primordial prevention of risk factors that are shared between diabetes and cancer. Also, the commonality of diabetes and cancer co-occurrence, particularly for Māori, reinforces the need for a multidisciplinary, joined-up approach to the detection and care of both conditions. Given the disproportionate burden of diabetes and those cancers that share risk factors with diabetes, action in these areas is likely to reduce ethnic inequities in outcomes from both conditions.

OA30 Systemic sclerosis and cancer in the UK: an epidemiological analysis using the Clinical Practice Research Datalink

Abstract Background/Aims After cardiopulmonary disease, cancer accounts for the highest proportion of deaths in systemic sclerosis (SSc), exceeding deaths attributed to renal disease and/or infection. Few population-based studies have assessed the burden of cancer in SSc. The present study investigated the association between cancer and SSc using the Clinical Practice Research Datalink (CPRD). Methods A validated case ascertainment strategy using combinations of diagnostic Read codes was applied to identify SSc patients in the CPRD with >12 months of data within the time period 01/01/1998 to 31/12/2017. A cohort study design examined cancer occurrence following a diagnosis of SSc. Patients with SSc were matched to six non-SSc comparators by age, sex and GP practice using incident density sampling. Prevalent and incident cases of SSc were analysed separately. Information on date and type of diagnosis of cancer was recorded. Descriptive statistics and Cox analyses determined hazard ratios for cancer occurrence. Results From 10.1 million individuals in the CPRD, 1,588 of cases of SSc were identified (85.3% female). We identified 206 cancers that occurred following a diagnosis of SSc (116 in prevalent cohort and 90 amongst incident cohort) (Table). The three commonest cancers were mucocutaneous (4.5%), lung (2.1%) and breast (1.9%). Lung cancer was significantly more common in SSc (Table). Incidence of cancer was higher in SSc (17 vs. 13.8 per 1000 person years) with adjusted hazard ratios of 1.41 (95% CI 1.14-1.75) for prevalent cases and 1.32 (95% CI 1.04-1.67) for incident SSc cases. We did not identify a strong relationship between cancer occurrence and SSc onset. Incidence of cancer increased with age at SSc diagnosis and was higher in males. Death from any cause at 6 months was higher in patients with SSc and cancer. Conclusion We have identified an increased risk of cancer occurrence (primarily mucocutaneous and lung) in patients with SSc from the UK, particularly amongst males and patients with higher age at SSc diagnosis. These findings could support screening recommendations for cancer in SSc. Disclosure J.D. Pauling: Consultancies; Astra Zenaca, Janssen, Permeatus Inc., Sojournix Pharma, Boehringer Ingelheim. Honoraria; Janssen. Member of speakers’ bureau; Janssen. J. Snowball: None. N. McHugh: None. A. McGrogan: None.

P105 Mode of hospital rheumatology appointments in people with rheumatoid arthritis: the impact of the pandemic in England

Abstract Background/Aims During the COVID-19 pandemic rheumatology services were advised to limit face to face contact, with remote telemedicine used instead. Although suitable for some people, issues have been highlighted with telemedicine. The frequency and proportion of remote appointments during the pandemic has not been described, or the socio-demographic characteristics of those accessing remote or in-person rheumatology care. This study aims to describe rheumatology healthcare utilisation and mode of appointment (remote/in-person) in people with rheumatoid arthritis (RA), prior to, and during the pandemic in England. Methods A retrospective prevalent cohort study of people with RA, identified using a validated algorithm, as of 1st April 2019 using electronic health record data (OpenSAFELY). Outpatient rheumatology appointments between 1st April 2019 and 31st March 2022 were identified. For each year, the number of outpatient appointments, mode of appointment (remote/in-person) and patient socio-demographic characteristics were described. Results 130,884 people with RA were identified. Since the start of the pandemic, the proportion of people without any appointments in a 12-month period increased from 28.5% in 2019/20 to 33.3% in 2020/21 and has not recovered. Older people were most frequently not seen (51% of people >80 years in 2020/21 and 2021/22). Of appointments where mode was known, 54.4% of people with appointments in the year from April 2020 were only seen remotely, reducing to 35.1% in the year from April 2021 (Table 1). The proportion with all remote appointments increased with increasing age, comprising 62% of people >80 years in 2020. This age gradient persisted in 2021, though proportions of those >80 years with all-remote appointments was lower (44%). Compared to urban dwellers, a higher proportion of those living in rural areas had all remote appointments in 2020 (58% vs 53%) and 2021 (38% vs 34%). Conclusion During the pandemic, one third of people with RA were not seen at all over a 12-month period and these were more frequently older people. Over half of people were only seen remotely in 2020, decreasing to one-third in 2021. Given the limitations of remote appointments it is unknown whether this increased frequency of remote appointments will impact long-term outcomes. Disclosure R.E. Costello: Shareholder/stock ownership; AstraZeneca. R.J. Hollick: None. M. Parker: None. J. Kennedy: None. B. Mackenna: None. S. Brophy: None. L. Tomlinson: None. J.H. Humphreys: None.