Hospitalization and change in body composition and strength in a population-based cohort of older persons

Abstract

Objectives: To examine the association between hospitalization and annual changes in body composition and strength in older adults.

Design: Cohort study.

Setting: Clinic examinations in Pittsburgh, Pennsylvania, or Memphis, Tennessee.

Participants: Well-functioning adults aged 70 to 79 who participated in the Health, Aging and Body Composition Study.

Measurements: Hospitalizations were reported at annual clinic visits and in semiannual phone interviews. In the event of death or reported hospitalization, hospitalizations were adjudicated according to medical record review. Dual X-ray absorptiometry (DXA) assessments of total, lean, and fat mass were conducted in six annual examinations, and measures of knee extensor strength were conducted in two annual examinations.

Results: DXA assessments followed 2,309 hospitalizations. In men and women, hospitalization in the previous year was associated with greater declines in total mass (-0.76 and -0.81 kg, respectively), fat mass (-0.41 and -0.54 kg), and lean mass (-0.33 and -0.25 kg) (P < .001 for all) than in nonhospitalized participants, after adjustment for demographics and baseline values. Hospitalization was associated with strength declines in men (-4.02 Nm, P = .046) but not in women. Relationships were similar after adjusting for health behaviors and chronic conditions, although the association between hospitalization and strength was attenuated. Associations increased with number of days hospitalized; hospitalizations totaling 8 days or more in the previous year were associated with significantly greater loss of total, lean, and fat mass and loss of strength in both sexes than in nonhospitalized participants.

Conclusion: Hospitalization is associated with significant changes in body composition and strength in older persons. These effects appear particularly important in persons hospitalized for 8 or more days per year.

Figure 1

Longitudinal Study Design

Figure 2. Adjusted 1-year changes in body composition and strength by days hospitalized in the last year (v. no hospitalization)†

†All models control for demographics, health behaviors (smoking, walking for exercise), and comorbidities (diabetes, cancer, cvd, arthritis, chronic lung disease, depression) and baseline values (of mass, fat mass, lean mass, or strength). Body composition N=1322 (men) and 1368 (women). Strength N=1051 (men) and 1043 (women).