Contextual and individual aspects of use of medication : Mutilevel studies on anxiolytic-hypnotic drug use, social context, adherence to medication, and disability pension

Aims Public health research today is greatly interested in individuals and the context in which they live, e.g., the area or neighborhood of residence. People living within the same area may be more similar to each other than to people living in other areas. Similar people may move to similar areas, and they also share area specific economic, lifestyle, and social factors, and health care availability, which might influence health and healthrelated behavior, beyond individual characteristics. We aimed to study contextual and individual aspects of use of medication, with special reference to anxiolytic-hypnotic drug (AHD) use, social context, adherence to medication, and disability pension, by applying multilevel analysis. Study I: (i) to identify and quantify a hypothesized collective effect of the neighborhood on women’s AHD use, and (ii) to analyze the general impact of neighborhood social participation on use of these medicines. Study II: to investigate (i) whether women living in the same neighborhood have similar propensity for disability pension that relates to neighborhood social participation, and (ii) whether there is an association between AHD use and disability pension in women that is modified by the neighborhood context. Study III: to investigate (i) whether the contextual component of the miniaturization of community concept (i.e., area high social participation and low trust) is associated with individual AHD use, and (ii) whether people living in the same area share a similar probability of AHD use, and if so, how large this contextual phenomenon is. Study IV: to investigate (i) whether any of the individual characteristics age, educational level, financial strain, self-rated health, social participation, and trust in the health care system are associated with primary non-concordance with medication (i.e., non-redemption of prescription), and (ii) whether people living in the same area have similar probability of primary non-concordance with medication that relates to area social participation. Study V: to examine (i) whether individual low social participation is associated with low adherence to antihypertensive medication, and (ii) whether this possible association is modified by the municipality of residence. Methods We used multilevel logistic regression analysis with individuals at the first level and areas (neighborhoods) at the second level. Both fixed effects (measures of association) and random effects (measures of variation) were investigated. In Study I and II, we used baseline data from The Malmö Diet and Cancer Study, a prospective cohort study performed in Malmö, Sweden. The 17 388 women, aged 45-73 years, who participated in the cohort, represented 41% of all women born 1923-1950 living in Malmö during the baseline period 1991-1996. A questionnaire and a 7-day personal diary were used to obtain information on relevant characteristics of the women, including use of medication. Study I: Of the 17 388 women in the cohort, 89% (n=15 456), with complete information on the variables studied, were included. Study II: Of the 17 388 women in the cohort, 70% (n=12 156), aged less than 65 years and with complete information on the studied variables, were included. In Study III and IV, we used data from the Life & Health year 2000 survey. A random sample of 70 044 people, aged 18-79 years living in central Sweden, had the opportunity to answer the postal questionnaire and 46 636 (67%) returned the questionnaire. Study III: Of the 46 636 participants, 82% (n=20 319 women and 17 850 men) had complete information on all the studied variables, and were therefore included. Study IV: Of the 46 636 participants, we included the 34% who reported having visited an emergency department, a physician at a hospital department, a primary care physician, or been admitted to a hospital during the last 3 months, and with complete information on all the variables studied (n=9 070 women and 6 795 men). In Study V, we used data from The Health Survey in Scania 2000, which was a postal questionnaire sent out to a random sample of 23 437 people aged 18-80 years living in Scania, Sweden. Study V: We included the 9.6% of the participants who indicated use of antihypertensives during the last year and who had complete information on all the variables studied (n = 1 288). Results Study I: Overall, 1.7% of the total individual differences in the probability of using AHDs were explained by the neighborhood level. This percentage, however, differed between different groups of individuals. Neighborhood rate of low social participation was associated with higher probability of AHD use (odds ratio (OR)= 3.10 (95% confidence interval (CI) 1.51-6.41)), independently of individual age, social participation, education, and living alone. This association decreased (OR= 2.01 (95% CI 0.97-4.14)) after additional adjustment for individual disability pension, self-rated health, self-reported stress, and medication for somatic disorders. Study II: Both AHD use (OR= 2.09 (95% CI 1.65-2.65)) and neighborhood rate of low social participation (OR=11.85 (95% CI 5.09-27.58)), 80% interval odds ratio 7.49-18.74, were associated with higher propensity for disability pension, after adjustment for individual characteristics. The association between AHD use and disability pension was not modified by the neighborhood context. The median odds ratio was 1.44 after adjusting for individual characteristics and 1.27 after additional adjustment for neighborhood social participation. Study III: The contextual component of the miniaturization of community concept was associated with individual AHD use (ORwomen = 1.39 (95% CI 1.19-1.63), 80% interval odds ratio 1.05-1.86, and ORmen = 1.26 (95% CI 1.03-1.54), 80% interval odds ratio 0.89-1.78), after adjustment for the individual variables age, education, and financial strain. Additional adjustment for the combinations of individual social participation/trust did not substantially weaken the association (ORwomen = 1.34 (95% CI 1.15-1.56), 80% interval odds ratio 1.02-1.75, and ORmen = 1.22 (95% CI 0.99-1.49), 80% interval odds ratio 0.86-1.73). The variation in AHD use between the areas was fairly small. Study IV: Younger age, financial strain, low self-rated health, and low trust in the health care system were associated with primary non-concordance with medication. However, area social participation was not related to primary non-concordance, and the variation in primary non-concordance between the areas was small. Study V: Individual low social participation was associated with low adherence to antihypertensives (OR = 2.05, 95% CI 1.05–3.99), after adjustment for age, sex, and education. However, after additional adjustment for self-rated health and psychological health, the association was not conclusive (OR = 1.80, 95% CI 0.90–3.61). Furthermore, the association between low social participation and low adherence to antihypertensives varied among municipalities in Scania (i.e., cross-level interaction). Conclusions In the Swedish setting, our results indicate that the social context seems to influence individual use of AHD and disability pension, possibly through individual characteristics. However, administrative area boundaries seem to play a minor role in understanding individual AHD use. On the contrary, women living in the same neighborhood appear to have similar propensity for disability pension, beyond individual characteristics. In addition, AHD use might increase the propensity for disability pension in women. People with younger age, financial difficulties, low self-rated health, and low trust in the health care system may have a higher probability of primary non-concordance with medication. However, the area of residence—as defined by administrative boundaries—seems to play a minor role for primary non-concordance. Also, individual low social participation seems to be associated with low adherence to antihypertensives, and this association may vary between different municipalities.