Polypharmacy is widespread in the elderly because of their multiple chronic health problems. The objective of this study was to investigate the prevalence and predictors associated with polypharmacy in a nationally representative sample of Korean elderly individuals. We used the Korea Health Insurance Review and Assessment Service – National Patient Sample (HIRA-NPS) data from 2010 and 2011. We used information on 319,185 elderly patients (aged 65 years or older) between January 1, 2010 and December 31, 2011 from the HIRA-NPS database. We defined ‘polypharmacy’ as the concurrent use of 6 medications or more per person, ‘major polypharmacy’ as 11 medications or more, and ‘excessive polypharmacy’ as 21 medications or more. The frequency and proportion (%) and their 95% confidence intervals were presented according to the polypharmacy definition. Polypharmacy was visualized by the Quantum Geographic Information Systems (QGIS) program to describe regional differences in patterns of drug use. Multivariate ordinal logistic regression was performed to estimate odds ratios (ORs) and their 95% confidence intervals (CI) to investigate the risk factors for polypharmacy. Of the Korean elderly studied, 86.4% had polypharmacy, 44.9% had major polypharmacy and 3.0% had excessive polypharmacy. Polypharmacy was found to be primarily concentrated in the Southwest region of the country. Significant associations between polypharmacy and the lower-income Medical Aid population (OR = 1.52, 95% CI 1.47, 1.56) compared with National Health Insurance patients was observed. Nationwide efforts are needed for managing polypharmacy among Korean elderly patients. In particular, a national campaign and education to promote appropriate use of medicines for the Medical Aid population is needed.
Objective To determine whether treatment with methylphenidate in children and young people with attention-deficit/hyperactivity disorder (ADHD) was associated with cardiovascular events. Design Self controlled case series analysis. Setting Nationwide health insurance database, 1 January 2008 to 31 December 2011, in South Korea. Participants 1224 patients aged ≤17 who had experienced an incident cardiovascular event and had had at least one incident prescription for methylphenidate. Main outcome measures A recorded diagnosis (either a primary or secondary cause) of any of the following cardiovascular adverse events: arrhythmias (ICD-10 (international classification of diseases, 10th revision) codes I44, I45, I47, I48, I49), hypertension (codes I10-I15), myocardial infarction (code I21), ischemic stroke (code I63), or heart failure (code I50). Incidence rate ratios were calculated with conditional Poisson regression and adjusted for time varying comorbidity and comedication. Results Increased risk of arrhythmia was observed in all exposed time periods—that is, periods of treatment with methylphenidate—(incidence rate ratio 1.61, 95% confidence interval 1.48 to 1.74), and the risk was highest in the children who had congenital heart disease. No significant risk of myocardial infarction was observed for all exposed time periods (1.33, 0.90 to 1.98), though risk was higher in the early risk periods between eight and 56 days after the start of treatment with methylphenidate. No significant increased risk was observed for hypertension, ischemic stroke, or heart failure. Conclusion The relative risk of myocardial infarction and arrhythmias is increased in the early period after the start of methylphenidate treatment for ADHD in children and young people. Though the absolute risk is likely to be low, the risk-benefit balance of methylphenidate should be carefully considered, particularly in children with mild ADHD.
OBJECTIVE Elevated serum ferritin has been known to be associated with the prevalence of metabolic syndrome (MetS). However, there was no research to examine whether serum ferritin levels have been actually associated with the prospective development of MetS. Accordingly, we carried out a prospective study to evaluate the longitudinal effects of baseline serum ferritin levels on the development of MetS. RESEARCH DESIGN AND METHODS A MetS-free cohort of 18,022 healthy Korean men, who had participated in a medical health checkup program in 2005, was followed until 2010. MetS was defined according to the joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention. Cox proportional hazards models were performed. RESULTS During 45,919.3 person-years of follow-up, 2,127 incident cases of MetS developed between 2006 and 2010. After adjusting for multiple covariates, the hazard ratios (95% CI) for incident MetS comparing the second quintile to the fifth quintile of serum ferritin levels versus the first quintile were 1.19 (0.98–1.45), 1.17 (0.96–1.43), 1.36 (1.12–1.65), and 1.66 (1.38–2.01), respectively (P for trend <0.001). These associations were apparent in the clinically relevant subgroup analyses. CONCLUSIONS Elevated serum ferritin levels were independently associated with future development of MetS during the 5-year follow-up period.