Hazard ratio for mortality, comparing calcitriol uses with nonusers, among subgroups. Results are stratified by site and adjusted for age, gender, race, eGFR, diabetes, coronary heart disease, Charlson comorbidity index; use of angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker, statin, erythropoietin, and oral calcium; body mass index; systolic BP; serum levels of albumin, calcium, PTH, and phosphate; and number of nephrology clinic visits in the previous year (model 3).