[Internal medicine in a group of 52 Spanish hospitals. Analysis of a case series and efficiency]

To analyze the case-mix and efficiency in a group of Services of Internal Medicine (IM) from 52 Spanish hospitals with routinary clinical information system.

From a total amount of 566,726 discharges during 1992, we studied the 71,430 corresponding to IM, analyzing the Minimum Basic Data Set and the Diagnosis-Related Groups (DRG). The hospitals were classified as level A (< 250 beds), B (251-599) and C (600 or over). We analyzed: Major Diagnostic Category (MDC); DRG, raw average length of stay (ALOS); outliers, trimmed ALOS; mortality; case-mix index; performance index; ajusted ALOS (by standard performance and case-mix); associated complications; number of diagnoses per discharge. A Chi-square test was used for qualitative variables and a mean-comparison test (independent data) for the quantitative ones.

Among the Internal Medicine Departments, IM was the Service that cared most patients, even more in the small-size hospitals. The most frequent DRG were: chronic obstructive pulmonary disease (COPD) 6.5% (DRG 088); simple pneumonia & pleuresy 6.1% (DRGs 089-090); heart failure 5.9% (DRG 127); stroke 4.5% (DRG 014); and angor pectoris 2.4% (DRG 140). The ALOS was shorter in the A-level hospitals (10.1 days) vs. B-level (11.6) and C-level (14.4). However, the trimmed ALOS was more homogeneous (A 8.8; B 9.9; C 11.7). The complexity indexes increased with the hospital level although the performance index also increased.

The IM services provide care for a high percentage of hospital patients, especially in the small-size centers. In these, less complex patients are seen, with decreased comorbidity, complications and mortality and they solve their patients with shorter ALOS than the IM services in the large-size hospitals.