Bennett 1992.

Methods	Retrospective cohort
Participants	3126 patients with AIDS and PCP. 82.6% Male Mean age= 31.1 years Age range=18‐65 years 40.4% White 33.2% Black 26.2% Hispanic
Interventions	1)CLINIC, HOSPITAL OR HOSPITAL WARD VOLUME OF HIV/AIDS PATIENTS High volume PCP hospital=160+ 1st episode of PCP. Low volume PCP hospital = less than 160 patient episodes in 1987 2)INCORPORATES TRAINEES IN CARE DELIVERY Major, Minor or None.
Outcomes	MEDICAL Mortality of Patients: a) Hospital volume 1)In‐hospital death: High (160+ cases of PCP) 20.7%. Low (Less than 160 cases of PCP) 30.1% P=<0.05 Adjusted Odds Ratio 0.64 (0.46‐0.88) P=0.05 2)Death within 30 days of admission: OR=0.51 (.36‐.73) P=0.05 3) LENGTH OF HOSPITAL STAY Low PCP=24.0 days High PCP= 24.3 days Not significant b) Major Teaching Affiliation: In‐hospital mortality: OR1.57 (.94‐2.62) 2) Death within 30 days: OR 1.34 (.77‐2.36)
Notes	Hospitals with less than 160 cases of PCP had double the in‐hospital mortality than higher volume hospitals. No association with teaching affilation noted for mortality.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	D ‐ Not used