Time effect on cardiometabolic risk indicators in patients with bipolar disorder: a longitudinal case-control study

Individuals with bipolar disorder are at increased risk for cardiovascular diseases. Most studies have described increases in cardiometabolic risk indicators (CMRIs) using clinical cut-off values. Further, there are no longitudinal studies on CMRIs. We aimed to investigate continuous measures of CMRIs in individuals with bipolar disorder and controls using both cross-sectional and longitudinal data. We used data from the Swedish St. Göran Bipolar project. Study individuals were examined at baseline and after a median of 6 and 7 years for the control and patient group, respectively. Data were collected December 2005-December 2020. The cohort included 281 individuals with bipolar disorder (mean age 39 years, 59% women) and 114 controls (mean age 38 years, 55% women). Of those, 155 patients and 74 controls also provided follow-up data. At baseline, individuals with bipolar disorder had significantly higher mean values of waist-to-hip ratio (WHR) (β = 0.142, p = 0.001), body mass index (β = 0.150, p = 0.006), plasma triacylglycerol (TAG) (β = 0.218, p < 0.001), total/plasma high-density lipoprotein-cholesterol (TChol/HDL-C) ratio (β = 0.103, p = 0.03), TAG/HDL-C ratio (β = 0.151, p = 0.006), and non-HDL-C (β = 0.168, p = 0.001) than controls. Most CMRIs remained higher in the patient group at follow-up. The difference between patients and controls increased over time for WHR (0.005 unit/year, p < 0.001), and systolic (1.1 mm Hg/year, p = 0.002) and diastolic (0.8 mm Hg/year, p < 0.001) blood pressure. Individuals with bipolar disorder displayed persistently higher levels of nearly all included CMRIs. Over time, a subset of CMRIs worsened in patients relative to controls. This suggests that active measures to counter cardiovascular risk in persons with bipolar disorder should be considered.