ORIGINAL ARTICLE Trans R Soc Trop Med Hyg 2023; 117: 255–259 https://doi.org/10.1093/trstmh/trac118 Advance Access publication 19 December 2022 Adjustments in case of overweight and obesity to the WHO tablet pole for praziquantel administration Antonio Montresor a, * , Pauline Mwinzi b , and Amadou Garba a a Department of Control of Neglected Tropical Diseases, World Health Organization, 1211 Geneva, Switzerland; b Expanded Special Programme for Elimination of Neglected Tropical Diseases, World Health Organization Regional Office for Africa, 00000 Brazzaville, Republic of Congo ∗ Corresponding author: Tel: 0041227913322; E-mail: montresora@who.int Received 10 June 2022; revised 7 October 2022; editorial decision 23 November 2022; accepted 30 November 2022 The WHO tablet pole was developed in 2001 to facilitate the distribution of praziquantel in large-scale treatment campaigns for the control of schistosomiasis. Although a number of field studies have confirmed the accuracy of the tool in normal individuals, some studies have demonstrated that overweight and obese individuals are underdosed. This article proposes an adjustment in the number of praziquantel tablets for treatment of indi- viduals who are overweight or obese according to their body mass index. We demonstrate that by adding an extra tablet of praziquantel to that indicated by the WHO tablet pole, the tool provides the appropriate number of tablets for treatment of overweight and obese individuals. We also propose a pictogram be included in the instructions for use of the WHO tablet pole. Introduction The World Health Organization (WHO) tablet pole was developed in 2001 1 to facilitate the distribution of praziquantel in preven- tive chemotherapy campaigns 2 for the control of schistosomiasis in countries where the presence of scales in the field is limited. Where functioning scales are available and well-functioning, they are preferable. However, the estimations provided by the tablet pole are important in case praziquantel distribution is organized outside of health settings (i.e. in school) where the availability of scales is limited. 1 The pole provides seven height intervals (separated by height thresholds: 0.94 m, 1.10 m, 1.25 m, 1.38 m, 1.50 m, 1.60 m and 1.78 m). The pole leans vertically against a wall and each individ- ual is classified into one of the height intervals, which corresponds to the number of praziquantel tablets (600 mg) to be adminis- tered (see Figure 1). The seven height intervals provided by the tablet pole were defined on the basis of a height–weight dataset that was pur- posefully collected in Guinea from 1667 individuals. 1 The WHO tablet pole performances were evaluated on the height and weight data for 25 000 individuals from 10 African countries in which schistosomiasis is endemic 1 and on the height and weight data for 9300 individuals in 11 non-African (endemic and non- endemic) countries. 3 The evaluation on data from African populations showed an appropriate dosage (30–60 mg/kg) in 98% of cases (range 86.6– 99.6%), underdosage in 0.8% of cases (range 0–4.7%) and over- dosage in 1.2% of cases (range 0–8.7%). 1 The evaluation on data from non-African populations showed an appropriate dosage in 98.2% of cases (range 94–100%), underdosage in 1% of cases (range 0–5.8%) and overdosage in 0.8% of cases (range 0– 2.4%). 3 The tablet pole was field tested 4–6 before being adopted by the WHO and widely used in the field. It was then produced as a strip of paper and included in all shipments of praziquantel donated through the WHO (>1 billion tablets shipped in 2010–2020). 7 However, since the introduction of the WHO tablet pole, the num- ber of overweight and obese individuals has increased as a result of changes in diet associated with rapid economic progress in var- ious areas of the developing world. 8–11 As a consequence, a num- ber of field studies have shown that while the WHO tablet pole performs well in normal individuals, in overweight and obese indi- viduals an inappropriate dose of praziquantel is frequently pro- vided. 5, 12, 13 For example, in a study in South Africa 12 where 35% of the female students were overweight or obese, the WHO tablet pole allowed administration of an adequate dose in only 73% of the sample. In a study from Mozambique, 13 while the pole per- formed well in children, only 81.7% of adult females received an appropriate dose. Obesity in schistosomiasis-endemic countries is directly asso- ciated with higher socio-economic status and is less prevalent in children. 14 Praziquantel is also active at a lower dosage 15 and the drug is considered to have a good safety profile. Even a dose of 60–80 mg/kg is unlikely to be of concern since praziquantel is known to be well tolerated at daily dosages of 100 mg/kg for 10 d © The Author(s) 2022. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com 255 Downloaded from https://academic.oup.com/trstmh/article/117/4/255/6932754 by guest on 05 April 2023