Purpose  Current research on potentially clinically significant drug-drug interactions (DDIs) in individuals with atrial fibrillation (AF) has predominantly focused on DDIs involving direct oral anticoagulants (DOACs), with limited evidence regarding other medications. Our study aimed to: (i) assess the overall prevalence of DDIs; (ii) investigate potential demographic correlates of DDIs; and (iii) examine the association of DDIs with adverse clinical outcomes in a nationwide cohort of older adults with AF and multimorbidity.

Methodology  Data from the Swedish national registers were linked to establish a cohort with a 2-year follow-up of adults ≥ 65 years who, on 1 January 2017, had a diagnosis of AF, ≥ 1 comorbidity and were prescribed ≥ 2 medications (n = 192,716). This study describes the prevalence of 72 potentially clinically significant DDIs from an adapted explicit international consensus list and a review focused specifically on DDIs involving DOACs. Correlates of DDIs were assessed through logistic regressions. Cox regression analyses were conducted to examine the association between DDIs and adverse clinical outcomes: overall and cardiovascular (CV) mortality, overall and CV hospitalisation, stroke, bleeding, and falls.

Results  In the overall population, 37.5% presented with ≥ 1 potential DDI, with CV (33.8%) and central nervous system (CNS) drugs (12.4%) most frequently involved. Sex, age, and civil status were most consistently associated with DDIs. Individuals with ≥ 1 DDI had a higher hazard of CV death (hazard ratio 1.28 95% confidence interval (CI) [1.24–1.32]), CV hospitalisation (1.12 [1.10–1.15]) and falls (1.06 [1.02–1.09]). DDIs with DOACs were associated with gastrointestinal bleeding (2.80 [1.35–5.81]). DDIs with CNS drugs were associated with stroke (1.19 [1.09–1.29]) and falls (1.32 [1.27–1.39]).

Conclusion  Potentially clinically significant DDIs were prevalent in older adults with AF and multimorbidity, with adverse clinical implications. Identifying these high-risk groups is essential for preventive strategies and effective clinical management.

Introduction: COVID-19 vaccinations have saved millions of lives, particularly among older adults. Rare potential adverse events have been reported in case reports, but risks among older adults remain unclear. This study assessed risks of selected potential adverse events in this population.

Methods: We included more than 2 million Swedish adults ≥65y in a nationwide register-based cohort. Post-vaccination risks were assessed for herpes zoster (HZ), encephalitis, myelitis and encephalomyelitis, multiple sclerosis (MS), myasthenia gravis, cranial nerve palsy, sudden sensorineural hearing loss (SSNHL), postinfectious arthritis and polymyalgia rheumatica (PMR) in several risk windows (1–30, 31–60, and 61–180 days) after each vaccine dose. Hazard ratios (HRs) with 95% confidence intervals (95%CIs) compared with unvaccinated were estimated by Cox regression adjusted for potential confounders. Sensitivity analyses included adding primary health care (PHC) visits, and applying analysis-specific 5-year disease-free wash-out periods.

Results: No increased HRs were observed for most outcomes. SSNHL showed increased HRs within 180 days after each dose [1.60 (95%CI 1.15–2.24); 1.43 (1.03–1.99); 1.61 (1.05–2.46) for dose 1, 2 and 3], with similar estimates across all three risk windows. Increased HRs were also seen for PMR after dose 2 [1.14 (1.04–1.24)] and dose 3 [1.16 (1.03–1.30)], with higher HRs during later time windows. HZ showed increased HRs in the sensitivity analysis with PHC visits, [1.19 (1.07–1.31); 1.31 (1.19–1.43); 1.42 (1.26–1.60) for dose 1, 2 and 3]. MS showed reduced risk after dose 3 in the sensitivity analysis with longer wash-out (targeting incident MS), but not in the main analysis (potential relapses included).

Conclusions: COVID-19 vaccines are generally safe in older adults, with very low incidence of the potential rare adverse events assessed. Slightly increased relative risks for SSNHL, PMR and HZ were observed, but these findings do not alter the overall benefit–risk profile of COVID-19 vaccination in older adults.

Introduction Multi-dose dispensing (MDD) is a medication management system in Sweden that pre-packages regularly used prescription medicines into unit doses. Despite widespread use, there are no recent national estimates of MDD prevalence in Sweden, and little is known about how use evolved through the coronavirus disease 2019 (COVID-19) pandemic or which patient groups account for most MDD utilisation.

Objective The purpose of this study was to describe the prevalence of multi-dose dispensing in older adults in Sweden from 2014 to 2023, spanning the COVID-19 pandemic, and describe trends by patient subgroups.

Methods We conducted a repeated cross-sectional study of older adults aged ≥ 70 years old in Sweden, 2014–2023. We used nationwide data from the Swedish Prescribed Drug Register linked at the individual level with several other administrative and healthcare registers. The primary outcome was annual period prevalence of MDD, stratified by age, sex, education level, living status, civil status, health status and geography.

Results Prevalence of MDD amongst adults aged 70 years or older increased by 1.5 percentage points between 2014 and 2023, reaching 12.1% in 2023, and there was no additional increase during the COVID-19 pandemic (2020–2022). In nursing home residents, MDD use approached near-universal levels (from 84.2 to 96.1%). Uptake also increased across other subgroups, most notably amongst people with a dementia diagnosis (+ 45.3 percentage points), those receiving home help services (+ 21.4 percentage points) and those with five or more chronic conditions (+ 15.3 percentage points). Over time, the characteristics of MDD users shifted towards community-dwelling adults receiving home help services, younger older adults (70–79 years old) and individuals with higher education.

Conclusions Our nationwide study indicates that MDD has become an established standard of medication management in Swedish nursing homes and is progressively extending into community settings amongst older adults with complex health needs. Prescribing of MDD remained stable during the COVID-19 pandemic. Future studies should quantify risks and benefits of MDD use especially in vulnerable, older, and frail populations.

Background: Several drugs have been linked to the risk of microscopic colitis (MC), a condition characterised by watery, non-bloody diarrhoea. Antibiotics can induce similar symptoms, but their connection to MC remains unclear.

Aim: To investigate the antibiotic-related risks of MC in adults aged 65 years and older.

Methods: This was a nationwide, self-controlled case series study including adults aged ≥ 65 years with a new prescription for antibiotics and biopsy-confirmed, incident MC (Sweden, 2007–17). We identified cases from the nationwide histopathology cohort ESPRESSO individually linked to several registers. Using conditional Poisson regression, we estimated incidence rate ratios (IRR) for four risk periods: on treatment, and 1–14, 15–91, and 92–365 days post-treatment, compared with the non-treatment periods in the same individual. We also conducted a negative control outcome analysis to assess whether the association was specific to MC or due to diagnostic workup. E-values were used to assess robustness to unmeasured confounding.

Results: We identified 2393 persons with incident biopsy-confirmed MC (median age at diagnosis 74; 67% women). Compared with the non-treatment periods, the risk of MC in the age-adjusted analysis increased with antibiotic treatment (IRR: 1.44 [95% CI: 1.13–1.84], E-value: 2.24), 1–14 days (IRR: 1.12 [0.83–1.49]), 15–91 days (1.12 [0.97–1.31]) and 92–365 days post-treatment (1.19 [1.07–1.32]). The negative control outcome analysis showed similar risks of biopsy-confirmed normal mucosa after antibiotic use.

Conclusion: The observed association between antibiotic use and MC may result from detection bias rather than a causal relationship.

Background: National estimates of drug discontinuation for deprescribing targets in older adults are limited, partly due to challenges distinguishing planned deprescribing from poor adherence. Focusing on individuals with multidose dispensing (MDD), characterized by high adherence by design, may yield realistic discontinuation rates.

Aims: To estimate the rates of discontinuation for chronically used drugs targeted for deprescribing among older adults, and to describe reinitiation among users of MDD and standard dispensing (non-MDD).

Methods: In this nationwide cohort study, Swedish adults aged ≥ 75 were identified from national registers. At baseline (1 January 2021), chronic users of seven drug classes were defined. We estimated the 12-month cumulative incidence of discontinuation (defined as no new dispensing during the treatment episode of the prior dispensing plus a 180-day grace period) and the proportion of patients restarting therapy within 180 days after discontinuation.

Results: We identified 162 518 chronic users: benzodiazepines (n = 69 511), PPIs (n = 43 973), antidepressants (n = 41 577), statins (n = 36 085), cholinesterase inhibitors (n = 6408), bisphosphonates (n = 5801) and antipsychotics (n = 4380). Discontinuation rates were low (8.3–51.5 per 1000 person-years), and non-MDD users had higher discontinuation and reinitiation rates across all drugs.

Conclusion: Discontinuation among Swedish older adults is infrequent. Irregular dispensing is likely misclassified as deprescribing, and MDD users may better reflect true discontinuation in routinely collected data.

Background  National register-based studies on the influence of dementia on COVID-19 infection and outcomes are scarce. This study aims to evaluate the risk of COVID-19 infection, hospitalization, and mortality among older persons with and without dementia.

Methods  This population-based observational study utilized real-world data based on the combination of various national registries in Sweden. Outcomes included COVID-19 infection, hospitalization, and mortality between 01 March 2020 (index date) and 31 August 2020, which was usually considered as the first wave of COVID-19 in Sweden. We used flexible parametric survival regression to estimate the hazard ratios (HRs) between people with and without dementia at different time points after the index date.

Results  We compared people with and without dementia, who were living in community dwellings (40,818 versus 1,984,503 persons) or nursing homes (31,826 versus 87,398 persons). In community dwellings, the HRs of COVID-19 infection increased from 2.08 in one month to 2.46 in two months, then decreased to 0.70 in six months after the index date. In nursing homes, the HRs declined throughout the follow-up period (from 1.89 in one month to 0.91 in six months). In community dwellings, the HRs of COVID-19 hospitalization increased from 1.40 in one month to 1.64 in six months after the index date. In nursing homes, the HRs was less than 1 in one month, and higher than 1 from four months after the index date, however, not statistically significantly. The HRs for COVID-19 mortality rose from 1.96 in one month to 2.39 in two months and dropped to 1.65 in six months in community dwellings; and declined from 2.27 in one month to 1.69 in six months in nursing homes.

Conclusions  In the first wave of COVID-19 in Sweden, higher risks of COVID-19 infection, hospitalization and mortality were observed in older persons with dementia compared to those without dementia, except for the risk of COVID-19 hospitalization in nursing homes. Further studies on the quality of care for persons with dementia are essential to prepare for future pandemics.

Objective: To investigate the age, period, and cohort effects of polypharmacy in older adults using Swedish register data covering the period 2006 to 2020.

Design: Repeated cross-sectional study using routinely-collected health care data.

Setting: Nationwide, Sweden.

Participants: A 10% random sample was drawn each year from the source population of all adults aged ≥ 65 in Sweden, 2006–2020 (cumulative n > 3,000,000).

Measurement: Polypharmacy was defined as the use of ≥ 5 medicines. Drug data were extracted from the National Prescribed Drug Register (NPDR) Medication use was assessed on 1st January (1-day point prevalence) each year based on the drug duration episodes. Age-Period-Cohort analysis was conducted to explore these effects.

Results: Overall, 32.8% of older adults was exposed to polypharmacy in 2020 compared to 28.6% in 2006. This increase was more pronounced among individuals aged 85 to 89, from while the prevalence remained relatively steady among those aged 65 to 84. In the formal Age-Period-Cohort analysis, the cohort differences were weak for polypharmacy, but more prevalent for specific medication classes.

Conclusion: Polypharmacy is mainly influenced by age and period effects, but not by cohort. The rise in polypharmacy is primarily propelled by an increased pace in medication use among individuals aged 75 to 89 years. These findings can provide valuable insights for making effective strategies aimed at reducing polypharmacy.

Purpose The STOPP/START criteria are frequently applied in observational studies to assess potentially inappropriate prescribing in older adults. This study aimed to assess the applicability of the three available STOPP/START versions in two distinct data sources.

Methods To evaluate the applicability of the three versions of STOPP/START criteria, we used two observational data sources: (i) Integrated Swedish administrative health registries (ISHR) encompassing routinely collected health data and (ii) the population-based Swedish National study on Aging and Care in Kungsholmen (SNAC-K), based on health professional-led clinical assessments. The Anatomical Therapeutic Classification code (ATC) was used to categorise medications. Diseases were categorised using the international classification of diseases version 10 (ICD10).

Results The first STOPP/START version demonstrated an applicability rate of 80% in ISHR and 84% in SNAC-K. The second version demonstrated an applicability of 64% in ISHR and 74% in SNAC-K. The third version showed an applicability of 66% in ISHR and 77% in SNAC-K. Challenges in applicability included broad definitions, vague terminology, and the lack of information on disease severity, symptomatic traits, and stability of certain conditions.

Conclusion The applicability of the STOPP/START criteria in observational studies seems to have decreased in more recent versions of the tool. Population-based studies with comprehensive clinical assessments may offer higher applicability compared to studies based on administrative data. Future versions of the STOPP/START criteria should prioritise clear and unambiguous definitions to improve their applicability in research and promote result generalisability and comparability.