Increased risk of coronary heart disease among patients with idiopathic inflammatory myositis: a nationwide population study in Taiwan.

OBJECTIVE: To evaluate the risk of incident coronary heart disease (CHD) among patients with DM and PM in a general population context. METHODS: We conducted a retrospective cohort study using the Taiwan National Health Insurance Research Database containing records covering the years from 2000 to 2010. DM and PM were confined for the purposes of this study to those aged ⩾18 years who were eligible for the Taiwan catastrophic illness certificate. The diagnoses, CHD outcomes and cardiovascular risk factors were identified from electronic claims data. We conducted two cohort analyses: CHD and DM, and CHD and PM, excluding for each analysis individuals with CHD already identified at baseline. Data for the comparison group was obtained from the Longitudinal Health Insurance database, comprising 1 million persons randomly sampled from the total beneficiaries during 2000. We estimated hazard ratios comparing myositis with comparison cohorts, adjusting for potential cardiovascular risk factors. RESULTS: A total of 1145 patients with idiopathic myositis were identified, along with 732 723 control patients aged ⩾18 years. The incidence rates of CHD were 15.1 in DM and 30.1 in PM per 1000 person-years, vs 8.4 and 10.5 per 1000 person-years in the comparison cohort. The adjusted hazard ratios for CHD in patients with idiopathic myositis were 2.21 (95% CI 1.64, 2.99) for DM and 3.73 (95% CI 2.83, 4.90) for PM. CONCLUSION: Results of this general population-based cohort study suggest that DM and PM are associated with an increased risk of CHD.

Assessing the effect of oral activated vitamin D on overall survival in hemodialysis patients: a landmark analysis.

BACKGROUND: Patients with end stage renal disease have a high all-cause and cardiovascular mortality. Secondary hyperparathyroidism and vitamin D deficiency are considered part of the mechanism for the excess mortality observed. We aimed to evaluate the relationship between vitamin D use and all-cause mortality. METHODS: In this retrospective cohort study, we included all incident patients who started hemodialysis in Taiwan between 2001 and 2009. Patients were followed from landmark time, i.e., the 360th day from hemodialysis initiation, through the end of 2010 or death. We evaluated the association between activated vitamin D use or not before landmark time and all-cause mortality using conditional landmark analysis with Cox regression. We used group-based trajectory model to categorize high-dose versus average-dose users to evaluate dose-response relationships. RESULTS: During the median follow-up of 1019 days from landmark time, vitamin D users had a lower crude mortality rate than non-users (8.98 versus 12.93 per 100 person-years). Compared with non-users, vitamin D users was associated with a lower risk of death in multivariate Cox model (HR 0.91 [95% CI, 0.87-0.95]) and after propensity score matching (HR 0.94 [95% CI, 0.90-0.98]). High-dose vitamin D users had a lower risk of death than conventional-dose users, HR 0.75 [95% CI, 0.63-0.89]. The association of vitamin D treatment with reduced mortality did not alter when we re-defined landmark time as the 180th day or repeated analyses in patients who underwent hemodialysis in the hospital setting. CONCLUSIONS: Our findings supported the survival benefits of activated vitamin D among incident hemodialysis patients.