Patient volumes and pre- and postdischarge postpartum infection: A retrospective cohort study

• High hospital volume is associated with high predischarge postpartum infections.
• High clinician volume may be associated with low predischarge infections.
• Misclassification of clinician volume might have biased these associations.
• We found no clear association between obstetric volume and postdischarge infection.

BackgroundTo examine the association between hospital and clinician obstetric volume and postpartum infection risk in the pre- and postdischarge periods.MethodsWe used data from the 2011 New York State Inpatient and Emergency Department Databases to fit generalized estimating equation models to examine the effect of hospital and clinician obstetric volume on infection before discharge and in the 30 days after discharge after delivery.ResultsHigher clinician volume was associated with lower predischarge infection risk (odds ratio [OR] for first vs third quartile was 0.84; 95% confidence interval [CI], 0.77-0.98). There was an uncertain trend toward higher predischarge infection risk in higher volume hospitals (OR for first vs third quartile was 1.36; 95% CI, 0.79-2.34). We found no associations between patient volumes and postdischarge infections; however, power was insufficient to rule out small associations. The joint association of hospital and clinician volumes with postdischarge infection appeared submultiplicative (product term OR = 0.95; 95% CI, 0.92-0.98).ConclusionThis study adds to the evidence that hospital obstetric volume is positively associated with predischarge postpartum infections, whereas clinician volume may be negatively associated with those predischarge infections. The associations between hospital obstetric volume and postdischarge infection appear to differ. These results underscore the importance of including postdischarge follow-up in hospital-based studies of postpartum infection.