Primary non-adherence to prescribed medication in general practice: lack of influence of moderate increases in patient copayment.

BACKGROUND: Primary non-adherence refers to the patient not redeeming a prescribed medication at some point during drug therapy. Research has mainly focused on secondary non-adherence. Prior to this study, the overall rate of primary non-adherence in general practice in Iceland was not known. OBJECTIVES: To determine the prevalence of primary non-adherence, test whether it is influenced by a moderate increase in patient copayment implemented in 2010 and examine the difference between copayment groups (general versus concession patients). METHODS: A population-based data linkage study, wherein prescriptions issued electronically by 140 physicians at 16 primary health care centres in the Reykjavik capital area during two periods before and after increases in copayment were matched with those dispensed in pharmacies, the difference constituting primary non-adherence (population: 200 000; patients: 21 571; prescriptions: 22 991). Eight drug classes were selected to reflect symptom relief and degree of copayment. Two-tailed chi-square test and odds ratios for non-adherence by patient copayment groups were calculated. RESULTS: The rate of primary non-adherence was 6.2%. It was lower after the increased copayment, reaching statistical significance for hypertensive agents, non-steroidal anti-inflammatory drugs (NSAIDs) and antipsychotics. Generally, primary non-adherence, except for antibacterials and NSAIDs, was highest in old-age pensioners. CONCLUSIONS: Primary non-adherence in Icelandic general practice was within the range of prior studies undertaken in other countries and was not adversely affected by the moderate increase in patient copayment. Older patients showed a different pattern of primary non-adherence. This may possibly be explained by higher prevalence of medicine use.

The gene encoding phosphodiesterase 4D confers risk of ischemic stroke.

We previously mapped susceptibility to stroke to chromosome 5q12. Here we finely mapped this locus and tested it for association with stroke. We found the strongest association in the gene encoding phosphodiesterase 4D (PDE4D), especially for carotid and cardiogenic stroke, the forms of stroke related to atherosclerosis. Notably, we found that haplotypes can be classified into three distinct groups: wild-type, at-risk and protective. We also observed a substantial disregulation of multiple PDE4D isoforms in affected individuals. We propose that PDE4D is involved in the pathogenesis of stroke, possibly through atherosclerosis, which is the primary pathological process underlying ischemic stroke.

Localization of a susceptibility gene for common forms of stroke to 5q12.

Stroke is one of the most complex diseases, with several subtypes, as well as secondary risk factors, such as hypertension, hyperlipidemia, and diabetes, which, in turn, have genetic and environmental risk factors of their own. Here, we report the results of a genomewide search for susceptibility genes for the common forms of stroke. We cross-matched a population-based list of patients with stroke in Iceland with an extensive computerized genealogy database clustering 476 patients with stroke within 179 extended pedigrees. Linkage to 5q12 was detected, and the LOD score at this locus meets the criteria for genomewide significance (multipoint allele-sharing LOD score of 4.40, P=3.9 x 10(-6)). A 20-cM region on 5q was physically and genetically mapped to obtain accurate marker order and intermarker distances. This locus on 5q12, which we have designated as "STRK1," does not correspond to known susceptibility loci for stroke or for its risk factors and represents the first mapping of a locus for common stroke.