RESUMO
OBJECTIVE: Previous cohort studies found robust associations of serum insulin-like growth factor I (IGF-I) and its main binding protein IGFBP-3 with increased morbidity or mortality. This study investigates the relationships between IGF-I and IGFBP-3 with health care costs and hospitalization in a general population and whether adding IGF-I or IGFBP-3 to a model of established health care predictors improves prediction. METHODS: Data from a population-based cohort study of 3139 men and women in Germany, aged 20 to 80 years at baseline were used (median follow-up time: 5.0 years). Self-reported physician visits, length of hospital stay were used to estimate annual costs. IGF-I and IGFBP-3 were categorized at the 10th and 90th percentile, to indicate 'low', 'intermediate', and 'high' concentrations, respectively. RESULTS: Total annual health care costs, with the major component of inpatient costs, and risk of hospitalization at baseline and follow-up were higher in subjects with low compared to intermediate IGF-I or IGFBP-3, after multivariable-adjustment. Subjects with low in contrast to intermediate IGF-I exhibited 30.6% higher annual total costs 5 years after baseline examination, corresponding to a difference in adjusted costs of EUR436.61. CONCLUSIONS: Low IGF-I and IGFBP-3 independently predict future health care costs and hospitalization. IGF-I or IGFBP-3 might be useful to identify subjects with excess health care use. The predictive performance of cross-sectional and longitudinal models of total and inpatient costs were slightly improved by adding IGF-I or IGFBP-3 but the cost-effectiveness of inclusion into prediction models needs to be examined.
