Objective. To determine whether longer stays of premature infants allowing for increased physical maturity result in subsequent postdischarge cost savings that help counterbalance increased inpatient costs.
Data Sources. One thousand four hundred and two premature infants born in the Northern California Kaiser Permanente Medical Care Program between 1998 and 2002.
Study Design/Methods. Using multivariate matching with a time-dependent propensity score we matched 701 “Early” babies to 701 “Late” babies (developmentally similar at the time the earlier baby was sent home but who were discharged on average 3 days later) and assessed subsequent costs and clinical outcomes.
Principal Findings. Late babies accrued inpatient costs after the Early baby was already home, yet costs after discharge through 6 months were virtually identical across groups, as were clinical outcomes. Overall, after the Early baby went home, the Late–Early cost difference was $5,016 (p<.0001). A sensitivity analysis suggests our conclusions would not easily be altered by failure to match on some unmeasured covariate.
Conclusions. In a large integrated health care system, if a baby is ready for discharge (as defined by the typical criteria), staying longer increased inpatient costs but did not reduce postdischarge costs nor improve postdischarge clinical outcomes.