Involuntary weight loss in older outpatients: incidence and clinical significance

Abstract

Objectives: To describe the incidence, anthropometric parameters, and clinical significance of weight loss in older outpatients.

Design: Four-year prospective cohort study.

Setting: University-affiliated Veterans Affairs Medical Center.

Patients: Two hundred forty-seven community-dwelling male veterans 65 years of age or older.

Measurements: Anthropometrics (weight, height, skin-folds, and circumferences), health status measures (Sickness Impact Profile scores, health care utilization, self-reported ratings of health), and bloodwork (cholesterol, albumin, others) were obtained at baseline and followed annually for 2 years. Outcome measures (hospitalization, nursing home placement, and mortality rates) were followed for a minimum of 2 years after any identified weight change.

Main results: The mean annual percentage weight change for the study population was -0.5% (SD: +/- 4.0%; range: -17% to +25%). Four percent annual weight loss was determined to be the optimal cutpoint for defining clinically important involuntary weight loss using ROC curve analysis. The annual incidence of this degree of involuntary weight loss was 13.1%. At baseline, involuntary weight losers were similar to nonweight losers in age (73.9 +/- 7.9 vs 73.3 +/- 6.7 years), body mass index (26.8 +/- 3.9 vs 26.9 +/- 4.1 kg/m2), and all other anthropometric, health status, and laboratory measures. Relative to nonweight losers, involuntary weight losers had significantly (P < or = .05) greater decrements in central skinfold and circumference measures (subscapular skinfolds, -2.9 vs -0.4 mm; suprailiac skinfolds, -4.2 vs -0.2 mm; and waist to hip ratio, -.01 vs + .00). Both groups had significant decreases in their triceps skinfolds (an estimate of peripheral subcutaneous fat), whereas arm muscle area and albumin levels did not decline significantly in either group. Over a 2-year follow-up period, mortality rates were substantially higher (RR = 2.43; 95% CI = 1.34-4.41) among involuntary weight losers (28%) than among nonweight losers (11%). Of interest, a similar increase in 2-year mortality (36%) was also observed among subjects with voluntary weight loss (by dieting). Survival analyses adjusting for differences between weight losers and nonweight losers in baseline age, BMI, tobacco use, and other health status and laboratory measures yielded similar results.

Conclusions: These results indicate that involuntary weight loss occurred frequently (13.1% annual incidence) in this population of older veteran outpatients. When involuntary weight loss occurred, the predominant anthropometric changes were decrements in measures of centrally distributed fat (trunkal skinfolds and circumferences). Finally, involuntary weight loss greater than 4% of body weight appears to be clinically important as an independent predictor of increased mortality.