The effect of antihelminthic treatment on subjects with asthma from an endemic area of schistosomiasis: a randomized, double-blinded, and placebo-controlled trial

Abstract

This is a prospective, double-blinded, and placebo-controlled trial evaluating the influence of antihelminthic treatments on asthma severity in individuals living in an endemic area of schistosomiasis. Patients from group 1 received placebo of Albendazole or of Praziquantel and from group 2 received Albendazole and Praziquantel. Asthma severity was assessed by clinical scores and by pulmonary function test. There was no significant difference in the asthma scores from D0 to D1-D7 after Albendazole or Praziquantel and from D0 to D30-90 after Albendazole or Praziquantel in both, group 1 and 2. It was observed, however, a clinical worsening of the overall studied population after 6 months and 12 months of antihelminthic treatments. Additionally, we observed increased frequency of forced expiratory volume in 1 second (FEV1) <80% on 12 and 18 months after treatment. The worsening of asthma severity after repeated antihelminthic treatments is consistent with the hypothesis of the protective role conferred by helminths in atopic diseases.

Figure 1

Flowchart of the study design.

Figure 2

Frequency of clinical scores of asthma in patients from Group 1 at day zero (D0) and one to seven days (D1–D7) after treatment with placebo (Plac) of Albendazole (Alb) and placebo of Praziquantel (PZQ) (a); and at day zero (D0) and one to seven days (D1–D7) after treatment with Albendazole or Praziquantel (Group 2) (b). Praziquantel was given seven days after the treatment with Albendazole in the Group 2. Data were represented as mean ± SD. There was no significant difference in the frequency of asthma scores between D0 versus D1–D7 in none of groups (P > 0.05; Chi-square Test for Independence).

Figure 3

Frequency of clinical scores of asthma at day zero (D0) and day 30 to day 90 (D30–D90) after treatment with placebo (Plac) of Albendazole (Alb) and placebo of Praziquantel (PZQ) (Group 1; (a)); and frequency of clinical scores of asthma at day zero (D0) and day 30 to 90 (D30–D90) after treatment with Albendazole and Praziquantel (Group 2; (b)). Data were represented as mean ± SD. (c) shows the frequency of clinical scores of asthma (0, 1, 2, 3, 4) at day zero (D0) and at 6 months, 12 months and 18 months after treatment with Praziquantel (Figure 3(c)). Patients were evaluated monthly from day 30 to day 90 (D30–D90). After 90 days of enrollment, both placebo and treatment groups were treated with Albendazole and Praziquantel. From there clinical scores of asthma were assessed each 6 months for a total period of 18 months. *D0 versus 6 m or D0 versus 12 m, P < 0.05; Fisher's exact test.

Figure 4

Frequency of Forced Expiratory Volume in 1 second (FEV1) <80% at D0, D7 after placebo of Albendazole treatment and D7 and D90 after placebo of Praziquantel treatments in the Group 1 and after treatments with Albendazole and Praziquantel in the Group 2 (Figure 4(a)). Frequency of FEV1 <80% at day zero (D0) and 6, 12 and 18 months after treatment with Albendazole and Praziquantel (b). Results were considered as normal when FEV1 value was ≥80%. Numbers in the top of the bars represent the percentage of patients who had FEV1<80%. *D0 versus 12 m, P < 0.05; **D0 versus 18 m, P = 0.0001; Fisher's exact test.