Older Medicare beneficiaries with diabetes who participated in an HMO-sponsored health club benefit had notable reductions in total health care costs at both 1 year (−$1,633, P
< 0.001) and 2 years (−$1,230, P
= 0.06) after program enrollment compared with similar enrollees who did not participate in the program. The cost savings were largely attributable to fewer hospital admissions and lower inpatient care costs with those hospitalizations. We also found that participation in the SS program of two or more visits/week on average in year 1 was associated with lower total health care costs in year 2 compared with less frequent participation. These results suggest that physical activity by older adults with diabetes has the potential to have an impact on the considerable economic burden of diabetes on the health care system and society (1
). This is the first study to show an association between reduced health care costs and participation in a health plan–sponsored health club benefit in a cohort of older adults with diabetes over a 2-year period.
While promising, these results should be interpreted with caution. Although we were able to adjust for a number of key variables that were available from automated administrative data, we were unable to account for all possible differences in factors that could have an impact on health care use and costs. The finding that SS participants had significantly more primary care visits and a higher preventive services index compared with control subjects suggests a potential selection bias and differences in health status and health-seeking behavior between the two groups. For instance, individuals who seek out more contact with the health care system might be more motivated to comply with medical treatments, engage in more health-screening activities, increase physical activity, improve their diet, or quit smoking. These behaviors may result in lower health care costs regardless of participation in a formal exercise program. We attempted to control for both health status and health-seeking behavior by including a measure of chronic disease burden, a summary preventive services index, and an empirically derived propensity score in our regression models; however, it is possible that the observed differences are still subject to residual confounding.
We used visits to the SS program as a proxy for physical activity and did not have data on the exact dose of exercise that members engaged in at the health clubs nor were we able to characterize the density or intensity of these visits. Information on physical activity that members engaged in outside of the program was also not available. It is plausible that the cost differences associated with SS participation may have been mediated by a direct effect of regular exercise on improved cardiometabolic risk factor control (7
) and fewer hospital admissions for acute hyperglycemic and cardiovascular complications. Other studies that have measured self-reported physical activity in older adults with diabetes (8
) or other comorbidities (25
) showed lower health care use or costs with higher levels of energy expenditure and walking duration. Di Loreto et al. (8
) reported dose-response effects of increasing energy expenditure on A1C and plasma lipids. Sustained reductions in A1C were associated with lower health care costs within 1–2 years in a large cohort of adults with diabetes from this same HMO (26
). A recent systematic review of diabetes disease management programs showed that in the short term, inpatient hospitalizations were reduced by a median of 18–31% in a general adult population (27
). Our findings of a 20–29% difference in hospital admissions in years 1 and 2 between SS participants and control subjects compare favorably to these disease management interventions.
Experimental studies have shown that higher volumes of exercise are associated with greater reductions in A1C (7
). Our exploratory analyses, which adjusted for potential confounding and selection bias, showed that participation in the SS program of two or more visits/week was associated with even greater cost savings. While promising, this finding should be interpreted with caution because the cost difference could primarily be due to the fact that healthier participants were able to participate more. Poor health, a greater number of comorbidities, and injuries have been associated with lower levels of physical activity in older adults (29
We showed that elective participation in a health club benefit was associated with notable reductions in total health care costs over 2 years in older adults with diabetes. We also showed that greater use of such benefits resulted in even greater cost reductions in the long term; however, the dose-response results should not be interpreted as a recommendation to encourage patients with diabetes to initiate intensive physical activity. Previous studies of exercise treatment in individuals with other chronic conditions suggested that exercise itself does not place patients at increased medical risk (31
), but a recent study showed higher than expected adverse events in middle- to older-aged patients with diabetes who participated in an aerobics and resistance exercise program compared with control subjects (38 vs. 14%) (28
). These dose-response findings are novel, but they need to be confirmed with randomized controlled trials that address self-selection and can more closely monitor older adults with diabetes who engage in moderate or strenuous exercise. Such a study would provide more definitive evidence about the health and economic outcomes of a health plan–sponsored health club benefit for older adults with chronic conditions such as diabetes.
Our findings do suggest that the health care cost reductions associated with health club participation for older adults in general (14
) also apply to older adults with diabetes. The impact on total health care costs are seen earlier and are of a threefold magnitude greater in this higher risk group. In contrast to the general older population that showed attenuated growth in total health care costs with greater participation, older adults with diabetes who made at least 2 visits/week to the SS program actually had reductions in total costs over time.