Caseload volume-outcome relation for pulmonary embolism treatment: association between physician and hospital caseload volume and 30-day mortality

Objective: This study sets out to examine the association between physician and hospital pulmonary embolism (PE) caseload volume and subsequent patient outcomes using 3-year nationwide population-based data in Taiwan. Method: This study used claims data from the 2002-2004 National Health Insurance Research Database. The sample of 2761 PE inpatients was divided into three physician caseload volume groups, < 3 cases (low volume), 3-6 cases (medium volume) and >= 7 cases (high volume), while the three hospital volume groups were < 42 cases (low volume), 42-110 cases (medium volume) and >= 111 cases (high volume). A conditional logistic regression model was performed to evaluate the effects of caseload volume on 30-day mortality for PE treatment. Results: Patients treated by low case volume physicians had significantly higher mortality rates than those treated by medium case volume (19.0% vs. 13.3%, P < 0.001) or high case volume physicians (19.0% vs. 8.4%, P < 0.001). However, no significant relationship was observed between 30-day morality and hospital caseload volume (P = 0.697). The regression shows that the adjusted odds of 30-day mortality among patients of low case volume physicians were over twice the mortality odds among patients of high case volume physicians (OR = 2.164, P < 0.001), and odds ratios were 1.401 relative to medium case volume physicians' patients (P < 0.05). Conclusion: We conclude that an inverse PE volume-outcome relationship does exist for physicians, but not for hospitals. The skill or experience of an individual physician is a more critical factor than hospital equipment, infrastructure or staffing team in determining PE patient outcomes.