The biggest gains came from areas where baseline performance was poor.
The researchers found NO consistent effect of P4P on intermediate health outcomes (low-strength evidence) and insufficient evidence to characterize any effect on patient health outcomes.
Finally, in hospital settings the researchers found that P4P had little or no effect on patient health outcomes but DID have a positive effect on reducing hospital readmissions.
Ambulatory Care P4P Program Analysis
The authors found nine studies which covered U.S. ambulatory care programs. Most tracked outcomes over 4 years with an average follow-up of 2.5 years.
One RCT found that individual incentives increased appropriate response to high blood pressure but not use of guideline-recommended antihypertensive medication.
Five of the six studies that reported positive results had a control group. Selection bias hurt the validity in three others because of the way the control group was chosen.
The two studies which were methodologically sound found no improvements in processes of care.
The 17 studies which originated in the United Kingdom generally showed process-of-care improvements although the evidence was mixed among the more methodologically rigorous studies.
Hospital-Based P4P Program Analysis
The authors found eight studies which looked at process-of-care measures in the hospital setting. Generally, those studies found no improvements in care processes.
The authors found that P4P programs generally did not decrease mortality or improve patient experience in five studies in hospital settings.
Even the high-quality failed to detect a link between P4P incentives and mortality and targeted conditions.
Interestingly one study found that hospital readmissions among Medicare fee-for-service patients decreased sharply for approximately two years after implementation of the Hospital Readmissions Reduction Program; improvements continued thereafter but at a substantially lower rate. Furthermore, readmission reductions were seen for various conditions and they decreased more among the measures that were specifically targeted by the P4P program than those that were not.
What Did We Learn?
The authors point out that this is largest systematic review to date regarding the effect of P4P programs.
Overall, in the ambulatory setting, the authors found limited evidence that P4P programs improved process-of-care outcomes over the short term (two to three years). Also, longer term was limited.
While many of the studies reviewed by the authors did find positive P4P effects the results were inconsistent and the magnitude of effect small.
There were methodological flaws throughout the studies reviewed. So, it was hard to connect any observed changes in outcomes to the P4P intervention itself.
Importantly, the findings of this systematic review were consistent with earlier systematic reviews—which also found that P4P programs have not been consistently effective in improving patient outcomes.
