Cost-effectiveness of screening for developmental dysplasia of the hip in Karachi, Pakistan using a universally applicable cost-effectiveness model

Abstract

Introduction: Developmental dysplasia of the hip (DDH) is a congenital anomaly of the hip socket that can lead to lifelong disability and pain when left untreated. DDH is a good candidate for screening because of its high frequency in population, availability of treatment and the possibility of secondary prevention. Pakistan currently does not have any systematic or universal neonatal screening programme for DDH.

Methods: The cost-effectiveness model in this study uses one decision tree for each screening scenario: (1) the status quo, (2) universal screening by clinical examination, (3) universal screening by clinical examination with targeted ultrasound (US) screening, (4) and universal screening by US. Loss of disability-adjusted life-years (DALYs) is used as outcome variable.

Results: When left untreated DDH creates a loss of 3.4 DALYs per person. Clinical examination and targeted US averts most DALYs per dollar spent. Generalised US averts more DALYs overall but requires a greater financial investment per DALY averted.

Conclusions: Universal US screening reaches more children and can be considered the more equitable approach but requires 10 times the financial investment clinical examination and targeted US requires. The decision which option is most appropriate for Karachi, Pakistan depends on resource availability, geography, infrastructure, treatment capacity, health system values and societal factors in Pakistan.

Keywords: Community Health; Secondary Prevention; economics.

Figure 1. Cost versus DALYs gained between different scenarios. DALYs, disability-adjusted life-years; US, ultrasound.

Figure 2. Sensitivity analysis of main variables in the model in relation to disability-adjusted life-years (DALYs) lost. ClinSens, sensitivity of screening by clinical examination; ClinSpec, specificity of screening by clinical examination; Comp, complication rate with Pavlik harness treatment; Compliance, compliance rate with Pavlik harness; DALYComp, DALYs lost due to complications after Pavlik treatment per 1000 children; DALYDDH, DALYs lost due to untreated DDH per 1000 children; DALYSurg, DALYs lost due to postsurgery sequelae per 1000 children; DALYTreat, DALYs lost due to DDH treated with a Pavlik harness; FU, cost of follow-up until maturity after Pavlik harness or surgical treatment for DDH; IniPav, initiates and completes treatment with Pavlik harness; Pav, cost of Pavlik harness per 1000 children; Prev, prevalence of DDH; RecScr, screening rate in absence of screening programme; Scr, cost of screening by clinical examination per 1000 children; ScrMat, screening rate at maternity ward; Surg, cost of surgical intervention for DDH per 1000 children; SurgAcc, percentage of children who are able to access surgical care; US, cost of ultrasound screening per 1000 children; US2nd, ultrasound attrition rate in second-stage screening programme; USAcc, ultrasound screening rate in case of universal ultrasound screening; USFU, cost of follow-up with ultrasound after diagnosis of immature hip anatomy (Graf type 2 a hips); USSens, sensitivity of screening by ultrasound; USSpec, specificity of screening with ultrasound; USTreat, percentage of children requiring Pavlik harness treatment in case of an abnormal ultrasound.

Figure 3. Sensitivity analysis of main variables in the model in relation to cost. ClinSens, sensitivity of screening by clinical examination; ClinSpec, specificity of screening by clinical examination; Comp, complication rate with Pavlik harness treatment; Compliance, compliance rate with Pavlik harness; DALYComp, disability-adjusted life-years lost due to complications after Pavlik treatment per 1000 children; DALYDDH, DALYs lost due to untreated DDH per 1000 children; DALYSurg, DALYs lost due to postsurgery sequelae per 1000 children; DALYTreat, DALYs lost due to DDH treated with a Pavlik harness; FU, cost of follow-up until maturity after Pavlik harness or surgical treatment for DDH; IniPav, Initiates and completes treatment with Pavlik harness; Pav, Cost of Pavlik harness per 1000 children; Prev, Prevalence of DDH; RecScr, Screening rate in absence of screening programme; Scr, Cost of screening by clinical examination per 1000 children; ScrMat, Screening rate at maternity ward; Surg, Cost of surgical intervention for DDH per 1000 children; SurgAcc, percentage of children who are able to access surgical care; US, cost of ultrasound screening per 1000 children; US2nd, ultrasound attrition rate in second-stage screening programme; USAcc, ultrasound screening rate in case of universal ultrasound screening; USFU, cost of follow-up with ultrasound after diagnosis of immature hip anatomy (Graf type 2 a hips); USSens, sensitivity of screening by ultrasound; USSpec, specificity of screening with ultrasound; USTreat, percentage of children requiring Pavlik harness treatment in case of an abnormal ultrasound.