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From a weighing scale to a pole: a comparison of two different dosage strategies in mass treatment of Schistosomiasis haematobium.

Nordin P, Poggensee G, Mtweve S, Krantz I - Glob Health Action (2014)

Bottom Line: We compared doses given by weight to doses given by height using descriptive statistics and regression.Our study shows that children with the same weight could qualify for up to four different dose levels based on their height.The largest variation of doses based on the WHO dose-pole will be found in children below 20 kg of bodyweight.

View Article: PubMed Central - PubMed

Affiliation: The Skaraborg Institute for Research and Development, Skövde, Sweden; per.nordin@skaraborg-institute.se.

ABSTRACT

Background: Clinical schistosomiasis in endemic countries is treated with a single dose of praziquantel per 40 mg/kg body weight. Treating according to weight, in resource-poor settings when thousands of doses are to be administered in mass treatment campaigns, is considered problematic. A calibrated dose-pole based on height was developed and is now used in mass treatment campaigns for determining the doses for schoolchildren. The dose-pole will generate dose errors since every child population contains individuals that are either short or tall for weight. The aim of this study is to explore whether the WHO praziquantel pole is a satisfactory dose instrument for mass treatment of S. haematobium.

Methods: In 1996 and 2002, 1,694 children were surveyed in the Kilimanjaro Region, Tanzania. We compared doses given by weight to doses given by height using descriptive statistics and regression.

Conclusions and interpretation: The WHO dose-pole for praziquantel is based on height of the patient; however, children with the same height will differ in weight. Our study shows that children with the same weight could qualify for up to four different dose levels based on their height. The largest variation of doses based on the WHO dose-pole will be found in children below 20 kg of bodyweight. Using bodyweight and tablet halves as the smallest tablet division unit to determine the doses of praziquantel, one only has to identify every 6th kilogram of bodyweight; the doses will then vary a lot less than when using the WHO dose-pole.

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Related in: MedlinePlus

Theoretical distribution of doses (mg/kg) in the case of an accurate scale and when the scale overestimates the weight by 2 kg.
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Figure 0007: Theoretical distribution of doses (mg/kg) in the case of an accurate scale and when the scale overestimates the weight by 2 kg.

Mentions: To illustrate that the scale-based method will provide doses with less inherent variation, we show two different scenarios in Fig. 7. Two measurement series are presented, one based on an accurate scale and one based on a scale which produces an overestimate of the weight by 2 kg. The hollow circles show the distribution of doses with an accurate scale using an arbitrary weight range from 5 to 83 kg. As shown before, the distribution of doses is not overlapping and is accurate as well, except for children with a weight below 15 kg. Below this weight the inherent variation starts to show. There is only one situation where the resulting dose goes slightly below 30 mg/kg, namely, at 12 kg body weight. The reason for this is not due to the scale, of course, but is a simple consequence of the fact that we are assuming tablet halves are the smallest practically possible division. If there was a way to easily and repeatedly divide this tablet into quarters or use a syrup preparation, this problem would cease to exist.


From a weighing scale to a pole: a comparison of two different dosage strategies in mass treatment of Schistosomiasis haematobium.

Nordin P, Poggensee G, Mtweve S, Krantz I - Glob Health Action (2014)

Theoretical distribution of doses (mg/kg) in the case of an accurate scale and when the scale overestimates the weight by 2 kg.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256524&req=5

Figure 0007: Theoretical distribution of doses (mg/kg) in the case of an accurate scale and when the scale overestimates the weight by 2 kg.
Mentions: To illustrate that the scale-based method will provide doses with less inherent variation, we show two different scenarios in Fig. 7. Two measurement series are presented, one based on an accurate scale and one based on a scale which produces an overestimate of the weight by 2 kg. The hollow circles show the distribution of doses with an accurate scale using an arbitrary weight range from 5 to 83 kg. As shown before, the distribution of doses is not overlapping and is accurate as well, except for children with a weight below 15 kg. Below this weight the inherent variation starts to show. There is only one situation where the resulting dose goes slightly below 30 mg/kg, namely, at 12 kg body weight. The reason for this is not due to the scale, of course, but is a simple consequence of the fact that we are assuming tablet halves are the smallest practically possible division. If there was a way to easily and repeatedly divide this tablet into quarters or use a syrup preparation, this problem would cease to exist.

Bottom Line: We compared doses given by weight to doses given by height using descriptive statistics and regression.Our study shows that children with the same weight could qualify for up to four different dose levels based on their height.The largest variation of doses based on the WHO dose-pole will be found in children below 20 kg of bodyweight.

View Article: PubMed Central - PubMed

Affiliation: The Skaraborg Institute for Research and Development, Skövde, Sweden; per.nordin@skaraborg-institute.se.

ABSTRACT

Background: Clinical schistosomiasis in endemic countries is treated with a single dose of praziquantel per 40 mg/kg body weight. Treating according to weight, in resource-poor settings when thousands of doses are to be administered in mass treatment campaigns, is considered problematic. A calibrated dose-pole based on height was developed and is now used in mass treatment campaigns for determining the doses for schoolchildren. The dose-pole will generate dose errors since every child population contains individuals that are either short or tall for weight. The aim of this study is to explore whether the WHO praziquantel pole is a satisfactory dose instrument for mass treatment of S. haematobium.

Methods: In 1996 and 2002, 1,694 children were surveyed in the Kilimanjaro Region, Tanzania. We compared doses given by weight to doses given by height using descriptive statistics and regression.

Conclusions and interpretation: The WHO dose-pole for praziquantel is based on height of the patient; however, children with the same height will differ in weight. Our study shows that children with the same weight could qualify for up to four different dose levels based on their height. The largest variation of doses based on the WHO dose-pole will be found in children below 20 kg of bodyweight. Using bodyweight and tablet halves as the smallest tablet division unit to determine the doses of praziquantel, one only has to identify every 6th kilogram of bodyweight; the doses will then vary a lot less than when using the WHO dose-pole.

Show MeSH
Related in: MedlinePlus