Improving timely childhood immunizations through pay for performance in Medicaid-managed care.

Despite widespread use of pay for performance (P4P) among commercial and government-sponsored health plans (Rosenthal et al. 2006; Kurhmerker and Hartman 2007;), there remains considerable uncertainty about how best to design and implement these programs (Dudley et al. 2004; Rosenthal et al. 2005; Petersen et al. 2006;). The Patient Protection and Affordable Care Act (PPACA) and Child Health Insurance Program Reauthorization Act (CHIPRA) contain legislation that will intensify the use of performance incentives (United States Congress 2009a, b). Experiments in payment policies will potentially build the evidence base for how to best use performance incentives to achieve higher quality, lower costs, and equity in the U.S. health care system. One area of uncertainty is the formula through which performance is translated into additional revenue. Many programs use “tournaments” or fixed achievement thresholds to determine whether providers merit additional pay (Centers for Medicare and Medicaid Services 2005). A theoretical argument exists, and some empirical evidence supports the notion that this model rewards providers who are already performing well while providing little incentive for quality improvement (Rosenthal et al. 2005; Chien et al. 2007a; Hayward 2007; Karve et al. 2008; Friedberg et al. 2010;). Paying providers a “piece-rate” for each patient meeting a performance benchmark (e.g., each diabetic receiving HbA1c testing twice a year) is one way to reward continual improvement. This payment scheme theoretically rewards continuous improvement in performance regardless of the baseline levels. It may also minimize incentives for providers to avoid high-risk or nonadherent patients from their practices or panels and thereby reduce the risk of exacerbating disparities (Hofer et al. 1999). Piece-rate performance incentives have been studied a handful of times particularly in conjunction with improving childhood immunization or well-child visit rates (Chien, Conti, and Pollack 2007b). Nearly 15 years ago, two randomized studies concluded that piece-rate P4P rewards were effective at improving immunization documentation in urban practices serving low-income patients (Fairbrother et al. 1999, 2001). These studies were performed at a time when the Centers of Disease Control (CDC) measured immunization rates using the 4 : 3 : 1 immunization series (four doses of vaccines against Diphtheria–Tetanus–Pertussis, three doses against Polio, and one dose of protection against Measles–Mumps–Rubella). Between 1999 and 2002, immunization recommendations evolved significantly to incorporate the development of new vaccines and guidelines for “catching up” children who experienced vaccination delays. By 2003, the CDC began measuring progress toward national childhood immunization goals using the 4 : 3 : 1 : 3 : 3 : 1 immunization series (the vaccines in the 4 : 3 : 1 series plus three doses against Haemophilus influenzae Type B, three against Hepatitis B, and one against Varicella Zoster Virus). This rate continues to be a core metric by which national, state, and local health agencies gauge their progress (Center for Disease Control and Prevention 2009). A recent study of piece-rate P4P evaluated the effectiveness of this strategy in raising attendance levels at the well-child visits in which the 4 : 3 : 1 : 3 : 3 : 1 immunization series is delivered. This study found that the two Medicaid-sponsored programs that raised rates more than the Medicaid national mean had combined their incentives with programmatic adjuncts like patient incentives and reminders (Felt-Lisk, Gimm, and Peterson 2007). “Piece-rate” payment strategies have a small but promising empirical base that warrants more rigorous examination. This study takes advantage of a natural experiment that occurred within the Medicaid health plans in New York State. One health plan introduced a distinctive piece-rate P4P program aimed at improving the childhood immunization rates as measured by the 4 : 3 : 1 : 3 : 3 : 1 series, while others attempted more conventional tactics (e.g., reminders and outreach to providers and parents without incentives) (Jacobsen Van JC 2005). Patient-level data allow us to explore whether the P4P program is associated with changes in immunization rates for specific patient subgroups. Although previous studies have not been able to examine whether children of racial/ethnic minority backgrounds or with chronic health conditions are differentially impacted by P4P programs, it is known that there is a paradoxical racial/ethnic disparity in immunization rates among those who live below the federal poverty line—Hispanics have the highest immunization rates (followed by blacks then whites) (Center for Disease Control and Prevention 2009).