Association of Insulin Resistance with Lower Glomerular Filtration Rate and All-Cause Mortality in the Korean Elderly Population: A Community-Based Prospective Cohort Study

Insulin resistance (IR) is a common metabolic disorder in chronic kidney disease patients. In the elderly population, it is not clear whether IR is associated with lower glomerular filtration rate (GFR) and mortality. Here, we analyzed the association between IR and GFR, all-cause mortality (ACM), or cardiovascular mortality (CVM) in the elderly population. This was a community-based prospective study. Participants were selected by random sampling from those aged >= 65 years in Seongnam, a satellite city of Seoul, Korea. A total of 743 participants were analyzed. IR was calculated using the homeostasis model assessment of insulin resistance (HOMA-IR). The mean age was 76.4 +/- 9.3 years. After multivariate analysis, HOMA-IR was negatively associated with GFR as a continuous variable (per 10 mL/min/1.73 m(2) increase, beta = -0.10, P = 0.004). Analyzing GFR as a categorical variable, HOMA-IR was still higher those with GFR < 60 mL/min/1.73 m(2) (GFR < 60 vs. 60-89 and >= 90 mL/min/1.73 m(2): 1.3 vs. 1.2 and 1.1, respectively; P = 0.025 and 0.019) by covariance analysis. During the follow-up period of 62.9 +/- 16.9 months, there were 168 (22.6%) cases of ACM and 47 (6.3%) cases of CVM. Those in the third quintile HOMA-IR group showed the lowest ACM rate, compared with the other quintiles (P < 0.001). CVM was not significantly associated with HOMA-IR. In conclusion, a lower GFR is associated with higher IR in the elderly population. Moreover, the lowest or the highest levels of HOMA-IR are associated with higher mortality rates.