Head lice treatments and school policies in the US in an era of emerging resistance: a cost-effectiveness analysis.
BACKGROUND
Head lice are a common infection in school-age children worldwide. Several authorities in the US have recommended different treatments and school policies in order to control this disease. Recent concerns of emerging lice resistance worldwide raise the necessity to reassess the current recommendations.


OBJECTIVE
To perform a cost-effectiveness analysis (from the US caregiver perspective) of three head lice treatments commonly used in the US, permethrin 1%, malathion 0.5% and the lice comb, in order to evaluate the cost effectiveness of different treatments in the current era, and to explore the effect of different factors in this analysis.


METHODS
We used a decision-tree model to represent the costs and effectiveness of the different treatment strategies. A patient/caregiver perspective was applied, with a time horizon of 2 weeks. Probabilities of treatment success or failure of the three treatments were based on the literature. Effectiveness was measured as the successful eradication of head lice, and costs - including the costs of the treatment, the physician co-pay and the costs of days out of school - were calculated. One-way and multi-way analyses were performed using decision analysis software (Treeage Pro Healthcare 2008).


RESULTS
Combing was dominated by permethrin 1%. The incremental cost-effectiveness ratio of malathion 0.5% versus permethrin 1% was $US161.75 per cure. For caregivers whose willingness to pay is <$US161.75 per cure, permethrin 1% is the most cost-effective option. For those with a willingness to pay of > or =$US161.75 per cure malathion 1% may offer the highest net monetary benefit. Twenty percent of the uncertainty in the model is due to variation in permethrin 1% resistance, and approximately 73% of the total variability of the model is attributed to the number of days the student has to be out of school because of the school's policy.


CONCLUSIONS
Our study suggests that permethrin 1% was the most cost-effective treatment for those with a willingness to pay of <$US162 per cure. Sensitivity of lice to permethrin and the specific school head lice policy had major effects on the model. Thus, informing communities in a given geographical area about the degree of head lice resistance and sensitivity is necessary in order for the public to make a rational decision regarding treatment. Schools' head lice policies have a major effect on the cost of head lice treatments.
Gur
Itzhak
I
Department of Family Medicine, University of Washington, Seattle, Washington, USA. gur008@gmail.com
Schneeweiss
Ronald
R
D000818:Animals; D002648:Child; D002675:Child, Preschool; D003362:Cost-Benefit Analysis; D003663:Decision Trees; D006291:Health Policy; D006801:Humans; D007305:Insecticide Resistance; D007306:Insecticides / Q000191:economics* / Q000627:therapeutic use*; D010373:Lice Infestations / Q000188:drug therapy* / Q000191:economics*; D008294:Malathion / Q000627:therapeutic use; D010374:Pediculus; D026023:Permethrin / Q000627:therapeutic use; D012574:Schools / Q000191:economics*; D016896:Treatment Outcome; D014481:United States
D007306:Insecticides; D026023:Permethrin; D008294:Malathion