Comparison of three methods for measuring multiple morbidity according to the use of health resources in primary healthcare

Objective: To compare three methods of measuring multiple morbidity according to the use of health resources (cost of care) in primary healthcare (PHC). Design: Retrospective study using computerized medical records. Setting: Thirteen PHC teams in Catalonia (Spain). Participants: Assigned patients requiring care in 2008. Main measurements: The socio-demographic variables were co-morbidity and costs. Methods of comparison were: a) Combined Comorbidity Index (CCI): an index itself was developed from the scores of acute and chronic episodes, b) Charlson Index (Chl), and c) Adjusted Clinical Groups case-mix: resource use bands (RUB). The cost model was constructed by differentiating between fixed (operational) and variable costs. Statistical analysis: 3 multiple lineal regression models were developed to assess the explanatory power of each measurement of co-morbidity which were compared from the determination coefficient (R-2), p< .05. Results: The study included 227,235 patients. The mean unit of cost was (sic)654.2. The CCI explained an R-2 = 50.4%, the Chl an R-2 = 29.2% and BUR an R-2 = 39.7% of the variability of the cost. The behaviour of the ICC is acceptable, albeit with low scores (1 to 3 points), showing inconclusive results. Conclusions: The CCI may be a simple method of predicting PHC costs in routine clinical practice. If confirmed, these results will allow improvements in the comparison of the case-mix. (C) 2011 Elsevier Espana, S.L. All rights reserved.