Association between inflammatory markers and frailty in institutionalized older men

Objectives: To determine whether higher serum levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high sensitivity C-reactive protein (CRP) were associated with frailty in the older institutionalized men.

Participants: The study enrolled 386 residents from a veterans care home in northern Taiwan in 2007. All participants were men. Residents younger than 65 years or with acute illness were excluded.

Methods: Frailty status was determined based on the frailty phenotype (indicators include weight loss, exhaustion, and low grip strength, slow walking speed). Participants with 3 or more of the indicators were defined as frail, with 1 or 2 as intermediate frail, with no as non-frail. Serum IL-6, TNF-α, and hsCRP levels were measured using enzyme-linked immunosorbent assay and modeled as tertile for severely skewed distributions.

Results: The mean age of the participants was 81.5±4.9 years. The percentages of frail were 33.2%, intermediate frail 59.1% and nonfrail 7.8%. Higher IL-6 level was positively associated with the frail status. Adjusting for age, body mass index, smoking status, and comorbid conditions, serum IL-6 showed significant trend across frailty categories (P=0.03 [95% CI 1.40-5.24]). No significant associations of TNF-α, and CRP level with frailty were observed. An IL-6 level of 1.79pg/mL had the optimal predictive value for frailty, with an area under the receiver operating characteristic (ROC) curve of 0.66 (P=0.01 [95% CI 0.53-0.78]).

Conclusion: Higher serum levels of IL-6 were associated with frailty status in the older institutionalized men with multiple comorbidities.