Cotrimoxazole with or without sulfadoxine-pyrimethamine reduces malaria in pregnant women

1 February 2011. Related: Women's health, Pregnancy.

Polly Clayden, HIV i-Base

In countries where malaria is rife, women receive sulfadoxine-pyrimethamine (SP) intermittent preventative therapy during pregnancy.

Several countries, including Malawi, recommend daily cotrimoxazole for all pregnant women to prevent opportunistic infections. WHO recommends that HIV-positive pregnant women receiving daily cotrimoxazole should not be given SP in order to avoid potential sulfa drug toxicity.

However no study has evaluated the effects of cotrimoxazole compared to SP in HIV-positive pregnant women.

A paper published in the 15 February 2011 edition of the Journal of Infectious Diseases, authored by Atupele Kapito-Tembo and colleagues, showed an analysis of the prevalence of malaria parasitaemia and anaemia in HIV-positive pregnant women taking daily cotrimoxazole, either with or without SP, compared to those just taking SP.

The study was conducted between 2005 and 2009 at Thyolo Hospital, Malawi. This hospital provides free antenatal care and has a well-established PMTCT programme.

The study was cross-sectional. It was possible because of confusion over implementation of recommendations for cotrimoxazole and SP during the study period. In the earlier years of the study, Malawian national policy for prevention of malaria in HIV-positive women was SP-IPT, later this changed to daily cotrimoxazole. This resulted in some women receiving both during the period of transition.

Women were enrolled from another study investigating the effects of iron supplementation on maternal morbidity. A total of 1142 women, were a median age of 27 years (range 16-46), with a median CD4 count of 423 cells/mm3 (range 11-1528). About 60% used bed nets and 48.5% received HAART.

Data on the use of SP and cotrimoxazole were available for 1121 (98.2%) women. Of these, 49.7% reported receiving SP only, 29.8% cotrimoxazole only and 15.5% received both. Only 5.1% reported receiving no prophylaxis. The women were similar with respect to CD4 count and clinical stage, but the women in the SP group were younger, less likely to use bed nets and less likely to be receiving ARVs compared to the women in the other groups.

The investigators found that the prevalence of PCR-detected malaria was nearly twice as high, 113/1128 (10%), than that of microscopic malaria, 61/1114 (5.5%). The prevalence of any anaemia and moderate to severe anaemia (haemoglobin <8g/dL) were 514/1140 (45.1%) and 18/1140 (1.6%) respectively.

After adjusting for age, gravidity, number of antenatal visits, bed net use and socioeconomic status, microscopic malaria infection was significantly lower in women taking cotrimoxazole plus SP, AOR 0.9 (95% CI, 0.01-0.66) or cotrimoxazole alone, AOR 0.44 (95% CI, 0.25-0.78) than in women taking SP alone. The odds for PCR-detected malaria were similar.

After adjusting for age, gravidity, number of antenatal visits, CD4 count and BMI, the presence of anaemia was also significantly lower in women taking cotrimoxazole plus SP, adjusted prevalence ratio (APR) 0.67 (95% CI 0.54-0.83) or cotrimoxazole only, APR 0.72 (95% CI, 0.61-0.83) than in women taking SP alone.

The investigators acknowledge several limitations to this study, particularly that changes in potential confounders may have occurred at the same time as the change in antimalarial prevention policy, and that controlling for these factors may leave residual confounding because the study was not randomised.

They also note that because women were only enrolled in the third trimester of pregnancy the impact of cotrimoxazole may be underestimated, as women are at an increased risk of malaria in the earlier stages of pregnancy.

They suggest that these results support the policy of daily cotrimoxazole instead of SP. Also, the observation the cotrimoxazole plus SP was more effective than cotrimoxazole alone warrants a randomised controlled study to look at both the efficacy and safety of this strategy.

Reference:

Kepito-Tembo et al. Marked reduction in prevalence of malaria parasitemia and anaemia in HIV-infected women taking cotrimoxazole with or without sulfadoxine-pyrimethamine intermittent preventative therapy during pregnancy in Malawi. J Infect Dis. Volume 203 Issue 4 February 15, 2011.
http://jid.oxfordjournals.org/content/203/4/464.abstract