The aim of our study was to assess the burden of thrombocytopenia according to antiretroviral therapy (ART), viremia and CD4-lymphocyte count of PLHIV in view of limiting the occurrence of this haematological disorder and optimizing the management of PLHIV in Yaoundé, Cameroon.
Our study population concerned all HIV positive people followed up in one of the health facilities in Yaoundé with a predominance of women (60.96%). This could be explained by a number of factors that promote the biological vulnerability of women to HIV [4]. Indeed, the female sex has a higher biological receptivity to HIV than the male sex [4]. Our results are consistent with the studies of Kouanfack et al.in 2010 and Essomba et al. in 2015 carried out in Cameroon, which obtained a female predominance of 70.6% and 66.3% respectively[5,6].
The median age of our study population was 40 years. This could be explained by the fact that HIV infection attacks young people who are sexually active, this being the case of the Yaoundé population. This median age is close to that obtained in Cameroon by Essomba et al. in 2015 who found 43 years[6].
In our study, 19.03% of subjects had thrombocytopenia; this result is different from that obtained by Tene et al.[7]in 2014 in Yaoundé Cameroon, which reported a prevalence of 13.67%. This can be explained by the fact that their study population of 139 participants was unrepresentative. On the other hand, our result is close to that obtained by Taremwa et al.[8] in southwestern Uganda in 2015,in which 17.4% was obtained and the 20% obtained by Alaei et al. [9]In Iran in 2000.
Depending on the severity of thrombocytopenia, the most predominant form was mild thrombocytopenia. The absence of severe thrombocytopenia can be explained by the fact that most of the patients followed up in Yaoundé who came for biological monitoring at the CIRCB were not in absolute emergency, and because most (79.0%) of these patients were on treatment.Furthermore it has been shown that an appropriate antiretroviral therapy is the most important step to fight thrombocytopenia[10].
Concerning severe immunodeficiency, 33.3% had thrombocytopenia. There was a positive and significant correlation between blood platelet count and CD4 count, which implies that a decrease in CD4 cell count may be accompanied by a decrease in blood platelet count. Taremwa and colleagues [8] in Uganda have also found a significant association between blood platelet count and CD4 T cell lymphocyte count (p <0.05).
Virological failure (viral load> 3log10) was present in 45.7% of thrombocytopenic patients. There was a negative and significant correlation between blood platelet count and plasma viral load, which could be explained by the fact that an increase in viral activity could be accompanied by a decrease in blood platelet count [11]. This result is in perfect agreement with that of O’Bryan et al.[10]in the United States of America in 2015 who also found an inverse correlation between platelet count and HIV viral load. It has been described during HIV infection that thrombocytopenia can occur by various mechanisms including bone marrow destruction induced by viral activity, antiretroviral therapy or immunological factors[11]. In Cameroon Mbanya et al. [12]in 2002 identified HIV as a cause of thrombocytopenia.
In our study, 6.9% of people on antiretroviral therapy had thrombocytopenia. This result is less than the 13% obtained by Taremwa and colleagues in Uganda[8], and higher than the 4.1% obtained by Wondinemeh et al.in Ethiopia[12]. 28.9% (11/38) of thrombocytopenic ART-treated patients were on AZT-containing therapies. This result could certainly suggest the involvement of AZT in the occurrence of drug induced thrombocytopenia [13]. On the other hand, 37% of antiretroviral-naïve patients had thrombocytopenia. This result is not in agreement with that obtained by Wankah et al. [14]at the Yaoundé teaching Hospital, which obtained 27.1%. This large difference in the frequency of thrombocytopenia among HIV patients in Yaoundé under ART compared to those naïve to ART reflects the findings by O’Bryan et al in the United States who showed decreased prevalence of thrombocytopenia in an HIV infected population as we moved from the pre-therapeutic periods to during early therapy and then to therapeutic periods with highly active antiretroviral drugs (HAART)[10].
After adjusting for sex, ART, viral load and CD4, viral load and ART exposure were significantly associated with decreased risk of thrombocytopenia. This result justifies the major implication and the protective effect of ART among risk of thrombocytopenia[15].