Polypharmacy and specific comorbidities in university primary care settings.

AIMS Polypharmacy is associated with adverse events and multimorbidity, but data are limited on its association with specific comorbidities in primary care settings. We measured the prevalence of polypharmacy and inappropriate prescribing, and assessed the association of polypharmacy with specific comorbidities. METHODS We did a cross-sectional analysis of 1002 patients aged 50-80years followed in Swiss university primary care settings. We defined polypharmacy as ≥5 long-term prescribed drugs and multimorbidity as ≥2 comorbidities. We used logistic mixed-effects regression to assess the association of polypharmacy with the number of comorbidities, multimorbidity, specific sets of comorbidities, potentially inappropriate prescribing (PIP) and potential prescribing omission (PPO). We used multilevel mixed-effects Poisson regression to assess the association of the number of drugs with the same parameters. RESULTS Patients (mean age 63.5years, 67.5% ≥2 comorbidities, 37.0% ≥5 drugs) had a mean of 3.9 (range 0-17) drugs. Age, BMI, multimorbidity, hypertension, diabetes mellitus, chronic kidney disease, and cardiovascular diseases were independently associated with polypharmacy. The association was particularly strong for hypertension (OR 8.49, 95%CI 5.25-13.73), multimorbidity (OR 6.14, 95%CI 4.16-9.08), and oldest age (75-80years: OR 4.73, 95%CI 2.46-9.10 vs.50-54years). The prevalence of PPO was 32.2% and PIP was more frequent among participants with polypharmacy (9.3% vs. 3.2%, p<0.006). CONCLUSIONS Polypharmacy is common in university primary care settings, is strongly associated with hypertension, diabetes mellitus, chronic kidney disease and cardiovascular diseases, and increases potentially inappropriate prescribing. Multimorbid patients should be included in further trials for developing adapted guidelines and avoiding inappropriate prescribing.

Cardiovascular disease in Switzerland - health care, mortality and geographical pattern

SUMMARY Switzerland is facing an aging population and a growing amount of patients with chronic diseases. It is crucial to display health care processes and pathways, to identify inequalities and obstacles, and to point out possibilities for improvements of the Swiss health care system (e.g. increase efficiency). The introductory part of the thesis presents a brief description of the Swiss health care system, health services research and regional variation as well as an introduction of CVD and its epidemiological key figures, aetiology and treatments. This is followed by the description of the utilized methods and data, and the objectives of this thesis. The subsequent sections present the four articles included in this thesis. The first article focuses on a small area analysis on regional variation of avoidable hospitalisations in Switzerland including density of primary care physicians and specialists, rurality and hospital supply factors as explanatory variables in the analysis. Lower rates of avoidable hospitalisations were found in areas with very high supply of primary care physicians, increased avoidable hospitalisation rates in areas with more specialists and in areas with higher proportion of rural residents. The second article aims to examine whether emergency patients with acute ST-segment elevation myocardial infarction were adequately treated, i.e. according to the treatment guidelines, in Switzerland. Results show that older and female patients were less likely to receive revascularization which suggests that the treatment guidelines may not be uniformly applied in Switzerland. Similar to the first article, also in the third article a small area analysis was performed but this time investigating regional variation in costs at the end of life. Strongest associations of cost was found with cause of death, age and language region of the decedents. The strong spatial variation of costs could only partly be explained by the included covariates. Article four aims to examine the relationship of distance to different hospital types and mortality from AMI or stroke. We found that AMI mortality in the Swiss population 30 and older and stroke mortality in those 65 and above increased with distance to central and university hospitals, while adjusting for sociodemographic and economic characteristics of the population. The presentation of the four articles is followed by a discussion, which summarizes the main findings and the strengths and limitations of the presented articles. The thesis concludes with a discussion about the challenges for policy, practice and future research.