Judging the effectiveness of clinical pathways for pneumonia: The role of risk adjustment
Context. Although observational studies suggest that clinical pathways may decrease costs and improve quality in hospitalized patients with community-acquired pneumonia, inferences from these studies are limited by potential selection bias and inadequate case-mix adjustment.
Objective. To compare the assessment of a clinical pathway for community-acquired pneumonia with and without adjusting for patient characteristics and disease
Design. Retrospective cohort study.
Patients and Setting. Consecutive series of adult patients admitted with clinical diagnosis of community-acquired pneumonia, treated with either a clinical pathway (which included guidelines for antibiotics, tests, and ancillary care) or usual care.
Main Outcome Measures. Total hospital charges, length of stay, clinical deterioration (requiring mechanical ventilation or intensive care unit transfer), and in-hospital mortality. We used multiple linear and logistic regression to adjust for patient case mix.
Results. Compared with patients receiving usual care (n=275), patients in the pathway group (n=97) were more likely to be treated by family physicians than specialists and had lower pneumonia severity scores. In the unadjusted analysis, total hospital charges were lower among pathway patients ($2456; 95% CI, $175 to $4737; P =0.04); in the adjusted analysis, the difference in total charges was smaller (average reduction $1807; CI, $4164 lower to $549 higher; P =0.13). In the unadjusted analysis, length of stay was lower among pathway patients (1.8 days lower; CI, 3.9 lower to 0.4 higher; P =0.12); in the adjusted analysis, the difference in length of stay was smaller (0.9 days lower; CI , 3.2 lower to 1.3 higher; P =0.4). Although unadjusted analysis showed significantly lower in-hospital mortality in pathway patients, this difference was not confirmed in the adjusted analysis.
Conclusions. Clinical pathways may reduce costs and improve quality of care in community-acquired pneumonia. In nonrandomized studies, however, selection bias and case-mix differences may explain some of the apparent effectiveness.