Data Sheet 1_Treating rheumatoid arthritis in Zanzibar: a cost effectiveness study comparing conventional, biologic, and targeted-synthetic disease modifying anti-rheumatic drugs.docx

Rheumatoid arthritis is a chronic inflammatory joint disease with low treatment coverage in sub-Saharan Africa. Effective treatment strategies are available. We aimed to evaluate the cost effectiveness of six disease modifying anti-rheumatic drug (DMARD) treat-to-target treatment strategies for patients with rheumatoid arthritis in Zanzibar. A Markov model was used to calculate the cost-effectiveness of various DMARD strategies in the treatment of rheumatoid arthritis over a 3-year period. A health-provider perspective was used and only outpatient costs were considered. The Clinical Disease Activity Index (CDAI) was utilized for measurement of efficacy and values were obtained from literature. Quality Adjusted Life Years (QALYs) were obtained from 122 patients attending the rheumatology clinic at Mnazi Mmoja Hospital. Data on costs were obtained from the central medical stores and hospital administration. Treatment strategies were given in sequential approach based on treat to target goals of therapy. This included methotrexate monotherapy, methotrexate + sulfasalazine + hydroxychloroquine, methotrexate followed by one or two biologic/targeted-synthetic DMARDs (b/tsDMARDs). Probabilistic and one way sensitivity analysis were performed. Scenario analysis was undertaken comparing drug prices from India and Scandinavia. Costs of therapy/patient/3 years ranged from USD 634 for methotrexate monotherapy and USD 5011 for methotrexate and two consecutive b/tsDMARDs. The highest and lowest effects were 2.209 and 2.079 QALYs gained from methotrexate therapy + two consecutive b/tsDMARDs and methotrexate monotherapy, respectively. From a healthcare provider perspective methotrexate monotherapy was the cost-effective option at a willingness to pay of USD 282. Pairwise comparison also favored methotrexate monotherapy as the feasible option. We found that increasing the willingness to pay led to a change in the most acceptable option from methotrexate monotherapy to methotrexate followed by b/tsDMARD. Methotrexate monotherapy is the cost-effective option for the management of rheumatoid arthritis in Zanzibar. Other options may be feasible if the willingness to pay threshold is increased or the drug prices are lowered, particularly for the b/tsDMARDs.

类风湿关节炎（Rheumatoid arthritis）是一种慢性炎症性关节疾病，在撒哈拉以南非洲地区治疗覆盖率较低。目前已有成熟有效的治疗策略。本研究旨在评估六种改善病情抗风湿药（disease modifying anti-rheumatic drug, DMARD）的达标治疗策略在桑给巴尔类风湿关节炎患者中的成本效益。研究采用马尔可夫模型（Markov model），计算三年内各类DMARD治疗方案治疗类风湿关节炎的成本效益。本研究从医疗服务提供者视角出发，仅纳入门诊成本进行分析。采用临床疾病活动指数（Clinical Disease Activity Index, CDAI）评估治疗疗效，相关疗效数据取自已发表文献。质量调整生命年（Quality Adjusted Life Years, QALYs）数据采集自姆纳齐·莫贾医院（Mnazi Mmoja Hospital）风湿科门诊的122名患者。成本数据来自中央医药商店及医院行政部门。治疗方案按照治疗目标采用序贯给药模式，具体包括：甲氨蝶呤单药治疗、甲氨蝶呤+柳氮磺吡啶+羟氯喹联合治疗，以及甲氨蝶呤序贯一种或两种生物/靶向合成改善病情抗风湿药（biologic/targeted-synthetic DMARD, b/tsDMARDs）。本研究开展了概率敏感性分析与单因素敏感性分析，并设置情景分析对比印度与斯堪的纳维亚地区的药品价格。每位患者三年内的治疗成本区间为：甲氨蝶呤单药治疗为634美元，甲氨蝶呤联合两种序贯生物/靶向合成改善病情抗风湿药为5011美元。疗效最高与最低值分别为：甲氨蝶呤联合两种序贯生物/靶向合成改善病情抗风湿药组获得2.209个质量调整生命年，甲氨蝶呤单药治疗组获得2.079个质量调整生命年。从医疗服务提供者视角来看，当支付意愿阈值为282美元时，甲氨蝶呤单药治疗为成本效益最优方案。两两比较结果同样支持甲氨蝶呤单药治疗为可行方案。研究发现，随着支付意愿阈值提升，最具临床可接受性的治疗方案从甲氨蝶呤单药治疗转变为甲氨蝶呤序贯生物/靶向合成改善病情抗风湿药。综上，甲氨蝶呤单药治疗是桑给巴尔地区类风湿关节炎管理的成本效益最优方案。若提升支付意愿阈值或降低药品价格（尤其是生物/靶向合成改善病情抗风湿药），其他治疗方案也可成为可行选择。