Oral candidiasis is a reliable marker of low CD4 counts and HIV disease progression in Zimbabwean women

Oral candidiasis (OC), or oral thrush, diagnosed by nurses was a simple and reliable marker of HIV disease progression in Zimbabwean women, according to the findings of a prospective study published in the April 15th edition of the Journal of Acquired immune Deficiency Syndrome.

An estimated 24.7 million people live with HIV/AIDS in sub-Saharan Africa where co-infection with tuberculosis (TB) is common. There are concerted national and international efforts to make antiretroviral drug treatment (ART) widely available. Daily cotrimoxazole (CTX) prophylaxis is recommended for all HIV/AIDS patients to ward off opportunistic infections.

Clinical decision-making to initiate CTX prophylaxis and ART depends on a combination of laboratory assays and key clinical findings. Laboratory tests - viral load and CD4 counts - are costly, require expensive equipment, a critical mass of highly trained technicians, and are largely available only in research settings.

Before access to ART became widely available, only a few rich patients were able to afford ART and the required clinical monitoring involving high-tech assays. However, as more and more patients gain access to ART, there is an urgent need for low-tech, simple, inexpensive tests which can be easily carried out by relatively untrained staff in poor rural and urban clinic settings. Such low-tech assays could be used to identify patients who need to start CTX prophylaxis and ART, and HIV-infected TB patients who require prophylaxis.

There is a clear inverse correlation between the prevalence of oral candidiasis, a common HIV-related oral disease, on one hand, and CD4 counts and ART use on the other. OC is therefore an important clinical finding from a diagnostic point of view and could complement low-tech assays such as manual total lymphocyte counts and haemoglobin counts in supporting clinical decision-making in resource-poor settings.

There is a paucity of studies on the usefulness of oral candidiasis as an accurate marker of HIV disease stage in clinic settings with no high-tech facilities. Previous studies of oral candidiasis in HIV/AIDS patients in Africa have relied on the diagnosis provided by dentists. Since most resource-poor settings do not have dentists, it is imperative that non-dental health care workers play a proactive role in the diagnosis of oral candidiasis.

Oral thrush is a fairly distinctive condition, usually presenting as white patches in the mouth, tongue or gums. The lesions may be painful and cause discomfort when eating.

A team of US and Zimbabwean researchers investigated the prevalence of oral candidiasis in relation to HIV sero-status and CD4 counts in Zimbabwean women, as well as the validity of diagnosis by trained nurses compared with that by an oral surgeon.

The study sites were family planning clinics in Harare, Zimbabwe. The study participants were women of reproductive age who were participating in two on-going HIV studies between November 2001 and November 2005; HIV testing and CD4 counts were carried out as part of the studies.

HIV-infected and HIV non-infected women received free dental care. OC was diagnosed by three nurses trained in the clinical diagnosis of HIV-related oral mucosal lesions and independently by an oral surgeon who was blinded to the patients’ HIV sero-status. All patients with oral mucosal lesions and OC received appropriate treatment.

A total of 461 (320 HIV-infected, 141 uninfected) women were seen by nurses and an oral surgeon within a two-week period. The median age of HIV-infected women was slightly higher than those of non-infected women (30 versus 27). One-third of the HIV-infected women had a CD4 count less than 200 cells/mm³.

Oral thrush was more common among HIV-infected women than in uninfected women. It was the most common lesion diagnosed in nearly one quarter of HIV-infected women, whereas hairy leukoplakia and Kaposi's sarcoma were found in less than 3%. The prevalence of OC diagnosed by nurses or the surgeon was a function of the CD4 count, being significantly higher among women with a CD4 count less than 200 cells/mm³ than in women with a CD4 count from 200 to 499 cells/mm³ or a CD4 count higher than 499 cells/mm³.

When diagnosis by the oral surgeon was used as a gold standard against which the nurses’ diagnosis was compared, there was a reasonably good agreement between the diagnoses by nurses and the surgeon. The statistics showed that a nurse correctly identified at least seven out of ten OC cases and nine out of ten non-OC cases.

In conclusion, the study results suggest that appropriately trained nurses can stage HIV disease in resource-poor settings through OC diagnosis, and that continuing education for nurses to correctly identify HIV-related clinical conditions such as OC can improve clinical decision-making for the care of HIV/AIDS patients in resource-poor settings.