Evaluating the impact of the nationwide public-private mix (PPM) program for tuberculosis under National Health Insurance in South Korea: A difference in differences analysis

Abstract

Author summary Why was this study done? With growing dominance of the private healthcare sector globally, majority of tuberculosis (TB) patients are seeking care in the private sector. Public-private mix (PPM) programs that can synergistically and comprehensively engage the private healthcare sector care into the national TB control efforts are integral in addressing TB care cascade disparities in the private sector. PPM interventions are widely being adopted by many high TB-burden countries with dominant private sectors, but current evidence is limited to small-scale pilot projects that were implemented in single or subregions less that did not sustain their operations for more than 2 years. To our knowledge, South Korea's PPM program is currently the only fully scaled up, long-standing nationwide program (formal inception in 2009). The South Korean experience can provide important insights on the long-term impact and policy gaps in integrating private sector TB care and patient management into the national TB control program. What did the researchers do and find? Using individual-level TB patient data registered in the Korean National Tuberculosis Surveillance System (KNTSS), we assembled cohort datasets classifying patients based on their primary institution reporting TB treatment registration (public versus private) in the respective years (2009 and 2014). Propensity score matching (PSM) using kernel method was performed to correct for imbalances in the observed covariates due to non-longitudinal and non-counterfactual nature in our data. Before the PPM program was formally implemented as a national program in 2009, private sectors institutions had suboptimal treatment outcomes compared to those in the public sector. Using difference in differences (DID) analysis, our study confirmed that the implementation and expansion of the nationwide PPM program was associated with a reduction in TB treatment outcomes gaps between the 2 healthcare sectors. What do these findings mean? To our knowledge, our study provides first long-term and comprehensive evidence of the policy level impact of the nationwide PPM program in reducing TB care disparities between the 2 healthcare sectors. Although significant improvements in TB treatment outcomes have been observed in the private sector, programmatic and policy adjustments may be needed to address TB care gaps experienced by TB patients transferring institutions during their treatment. Our study provides important evidence, insights, and future directions for countries that aims to strengthen and scale up PPM programs for TB alongside the efforts to introduce social health insurance. The South Korean experience highlights the importance of strengthening the financial governance and regulatory mechanisms in implementing and scaling up the PPM intervention to streamline national TB control efforts. Background Public-private mix (PPM) programs on tuberculosis (TB) have a critical role in engaging and integrating the private sector into the national TB control efforts in order to meet the End TB Strategy targets. South Korea's PPM program can provide important insights on the long-term impact and policy gaps in the development and expansion of PPM as a nationwide program. Methods and findings Healthcare is privatized in South Korea, and a majority (80.3% in 2009) of TB patients sought care in the private sector. Since 2009, South Korea has rapidly expanded its PPM program coverage under the National Health Insurance (NHI) scheme as a formal national program with dedicated PPM nurses managing TB patients in both the private and public sectors. Using the difference in differences (DID) analytic framework, we compared relative changes in TB treatment outcomes-treatment success (TS) and loss to follow-up (LTFU)-in the private and public sector between the 2009 and 2014 TB patient cohorts. Propensity score matching (PSM) using the kernel method was done to adjust for imbalances in the covariates between the 2 population cohorts. The 2009 cohort included 6,195 (63.0% male, 37.0% female; mean age: 42.1) and 27,396 (56.1% male, 43.9% female; mean age: 45.7) TB patients in the public and private sectors, respectively. The 2014 cohort included 2,803 (63.2% male, 36.8% female; mean age: 50.1) and 29,988 (56.5% male, 43.5% female; mean age: 54.7) patients. In both the private and public sectors, the proportion of patients with transfer history decreased (public: 23.8% to 21.7% and private: 20.8% to 17.6%), and bacteriological confirmed disease increased (public: 48.9% to 62.3% and private: 48.8% to 58.1%) in 2014 compared to 2009. After expanding nationwide PPM, absolute TS rates improved by 9.10% (87.5% to 93.4%) and by 13.6% (from 70.3% to 83.9%) in the public and private sectors. Relative to the public, the private saw 4.1% (95% confidence interval [CI] 2.9% to 5.3%, p-value < 0.001) and -8.7% (95% CI -9.7% to -7.7%, p-value <0.001) higher rates of improvement in TS and reduction in LTFU. Treatment outcomes did not improve in patients who experienced at least 1 transfer during their TB treatment. Study limitations include non-longitudinal nature of our original dataset, inability to assess the regional disparities, and verify PPM program's impact on TB mortality. Conclusions We found that the nationwide scale-up of the PPM program was associated with improvements in TB treatment outcomes in the private sector in South Korea. Centralized financial governance and regulatory mechanisms were integral in facilitating the integration of highly diverse South Korean private sector into the national TB control program and scaling up of the PPM intervention nationwide. However, TB care gaps continued to exist for patients who transferred at least once during their treatment. These programmatic gaps may be improved through reducing administrative hurdles and making programmatic amendments that can help facilitate management TB patients between institutions and healthcare sectors, as well as across administrative regions.