Developing a measure of prenatal case management dosage

Recently, federal funding was designated through the Patient Protection and Affordable Care Act giving states the opportunity to expand their prenatal case management programs (PCM) through home visitation. Studies evaluating the effect of PCM on birth outcomes have shown little or no positive results. One suggested reason for these findings is a lack of attention in the assessment of dosage. The objective of this study is to demonstrate the use of measuring PCM dosage when assessing pregnancy outcomes. A birth cohort (N = 4,582) encompassing Medicaid-insured Iowa residents enrolled in PCM who gave birth to a singleton from October 2005 to December 2006 was constructed from linked Iowa birth, Medicaid Claims, and Women's Health Information Systems datasets. Data was used to create a dosage measure capturing the duration of enrollment, amount of time spent with a case manager, and breadth of interventions. Bivariate analysis and logistic regression were used to assess the relationship between PCM dosage and the birth outcomes. Dosage was significantly associated with LBW (X (2) = 31.1, P < 0.001) and PTB (X (2) = 56.2, P < 0.001). After adjustment for potential confounders, the likelihood of LBW and PTB were aOR: 0.47 (95% CI: 0.36-0.63) and aOR: 0.60 (95% CI: 0.44-0.82) for women with medium dosage (compared to low dosage), respectively. For women with high PCM dosage the likelihood of LBW and PTB was aOR 0.40 (95% CI: 0.31-0.51) and aOR = 0.62 (95% CI: 0.48-0.81), respectively. This study showed that PCM dosage was significantly associated with lower odds of an adverse pregnancy outcome occurring.