Adult Hematology and Clinical Chemistry Laboratory Reference Ranges in a Zimbabwean Population.

BACKGROUND: Laboratory reference ranges used for clinical care and clinical trials in various laboratories in Zimbabwe were derived from textbooks and research studies conducted more than ten years ago. Periodic verification of these ranges is essential to track changes over time. The purpose of this study was to establish hematology and chemistry laboratory reference ranges using more rigorous methods. METHODS: A community-based cross-sectional study was carried out in Harare, Chitungwiza, and Mutoko. A multistage sampling technique was used. Samples were transported from the field for analysis at the ISO15189 certified University of Zimbabwe-University of California San Francisco Central Research Laboratory. Hematology and clinical chemistry reference ranges lower and upper reference limits were estimated at the 2.5th and 97.5th percentiles respectively. RESULTS: A total of 769 adults (54% males) aged 18 to 55 years were included in the analysis. Median age was 28 [IQR: 23-35] years. Males had significantly higher red cell counts, hemoglobin, hematocrit, and mean corpuscular hemoglobin compared to females. Females had higher white cell counts, platelets, absolute neutrophil counts, and absolute lymphocyte counts compared to males. There were no gender differences in eosinophils, monocytes, and absolute basophil count. Males had significantly higher levels of urea, sodium, potassium, calcium, creatinine, amylase, total protein, albumin and liver enzymes levels compared to females. Females had higher cholesterol and lipase compared with males. There are notable differences in the white cell counts, neutrophils, cholesterol, and creatinine kinase when compared with the currently used reference ranges. CONCLUSION: Data from this study provides new country specific reference ranges which should be immediately adopted for routine clinical care and accurate monitoring of adverse events in research studies.

Hematological and biochemical laboratory reference intervals for Zimbabwean adolescents.

BACKGROUND: Reference intervals are used as an aid in the interpretation of laboratory results. Most developing countries do not have reference intervals specific to adolescents. This study was aimed at establishing hematological and biochemical reference intervals for adolescents aged ≥ 12 years to < 18 years. METHODS: A community based, cross sectional study was conducted using the multistage sampling technique. Participants were enrolled from the UZ-UCSF research study catchment areas of Harare, Chitungwiza, and Mutoko. Samples were transported for analysis at the UZ-UCSF Central Laboratory under recommended conditions. The data analysis presented in this paper is for 302 adolescents aged ≥ 12 to < 18. Non-parametric statistical methods were used to estimate the 95% reference limits for the hematological and biochemical parameters, with the lower limit defined as the 2.5 percentile and the upper limit defined as the 97.5 percentile of the distribution. RESULTS: A total of 302 adolescents were included. Results show significant differences between males and females in hematological parameters except platelets, eosinophils, basophils, and red cell distribution width. The biochemical parameters which showed significant differences between males and females were phosphate, ALP, ALT, AST, GGT, and lipase. CONCLUSIONS: Hematological indices and liver function tests differ significantly by gender and this should be considered when defining normal intervals.

Predictors of attrition among children born in a PMTCT programme in Zimbabwe followed up over 5 years.

Eliminating of paediatric HIV within prevention of mother to child transmission (PMTCT) interventions rests on complete follow-up of all children. We report on predictors of child attrition in the PMTCT cascade over 5 years where 1050 pregnant women were enrolled at 36 gestational weeks. Mother and child pairs were followed up at birth, 6 weeks, 4 months, 9 months, and every 6 months thereafter for 60 months. Higher attrition was observed for children of economically advantaged, socially stable mothers regardless of HIV status, whereas compliance was observed for children whose mothers tested positive for HIV-1, HSV-2 and Syphilis. Low birthweight was associated with attrition regardless of maternal HIV status. Five years predictors of attrition did not differ by maternal HIV status, as HIV-exposed children succumbed to mortality and those not exposed were loss to follow-up (LFU). Child follow-up is influenced more by maternal lifestyle and health risks leading to retention of high-risk children in PMTCT programmes.

The incidence of HIV among women recruited during late pregnancy and followed up for six years after childbirth in Zimbabwe.

BACKGROUND: HIV incidence is a useful tool for improving the targeting of populations for interventions and assessing the effectiveness of prevention strategies. A study in Harare, Zimbabwe reported cumulative incidences of 3.4% (3.0-3.8) and 6.5% (5.7-7.4) among post-partum women followed for 12 and 24 months respectively between 1997 and 2001. According to a Government report on HIV the prevalence of HIV fell from about 30% in 1999 to 14% in 2008. The purpose of this study was to determine the incidence of HIV-1 among women enrolled during late pregnancy and followed for six years after childbirth and to identify risk factors associated with acquisition of HIV. METHODS: HIV-uninfected pregnant women around 36 weeks gestation were enrolled from primary health care clinics in peri-urban settlements around Harare and followed-up for up to six years after childbirth. At every visit a questionnaire was interview-administered to obtain socio-demographic data and sexual history since the previous visit. A genital examination was performed followed by the collection of biological samples. RESULTS: Of the 552 HIV-uninfected women 444 (80.4%) were seen at least twice during the six years follow-up and 39 acquired HIV, resulting in an incidence (95% CI) of 2.3/100 woman-years-at-risk (wyar) (1.1-4.1). The incidence over the first nine months post-partum was 5.7/100 wyar (3.3-8.1). A greater proportion of teenagers (15.3%) contributed to a high incidence rate of 2.9/100 (0.6-8.7) wyar. In multivariate analysis lower education of participant, RR 2.1 (1.1-4.3) remained significantly associated with HIV acquisition. Other risk factors associated with acquisition of HIV-1 in univariate analysis were young age at sexual debut, RR 2.3, (1.0-5.6) and having children with different fathers, RR 2.7(1.3-5.8). Women that knew that their partners had other sexual partners were about four times more likely to acquire HIV, RR 3.8 (1.3-11.2). CONCLUSION: The incidence of HIV was high during the first nine months after childbirth. Time of seroconversion, age and educational level of seroconverter are important factors that must be considered when designing HIV intervention strategies.

Vaginal practices of HIV-negative Zimbabwean women.

BACKGROUND: Vaginal practices (VPs) may increase HIV risk by injuring vaginal epithelium or by increasing risk of bacterial vaginosis, an established risk factor for HIV. METHODS: HIV-negative Zimbabwean women (n = 2,185) participating in a prospective study on hormonal contraception and HIV risk completed an ancillary questionnaire capturing detailed VP data at quarterly followup visits for two years. RESULTS: Most participants (84%) reported ever cleansing inside the vagina, and at 40% of visits women reported drying the vagina using cloth or paper. Vaginal tightening using cloth/cotton wool, lemon juice, traditional herbs/powders, or other products was reported at 4% of visits. Women with ≥15 unprotected sex acts monthly had higher odds of cleansing (adjusted odds ratio (aOR): 1.17, 95% CI: 1.04-1.32). Women with sexually transmitted infections had higher odds of tightening (aOR: 1.42, 95% CI: 1.08-1.86). CONCLUSION: Because certain vaginal practices were associated with other HIV risk factors, synergism between VPs and other risk factors should be explored.

Risk factors for herpes simplex virus type 2 and its association with HIV among pregnant teenagers in Zimbabwe.

Herpes simplex virus type 2 (HSV-2) causes a chronic infection that is recognised as the leading cause of genital ulcer disease worldwide and is known to increase the risk of HIV infection. In a cross-sectional study we examined risk factors for HSV-2 among 176 pregnant teenagers recruited from three primary health care clinics in Zimbabwe. The prevalence of HSV-2 and HIV were 41.6% and 29.2% respectively. HIV-infected teenagers were more likely to be HSV-2 seropositive compared with the HIV uninfected teenagers, odds ratio (OR) 7.9 (95% confidence interval (CI) 3.7-16.9). In multivariate analysis having an older partner remained independently associated with HSV-2 seropositivity, OR 2.9 (95% CI 1.2-6.9) suggesting that risk factors for HSV-2 seropositivity among pregnant teenagers depend primarily on the behaviour of the male partners.

The prevalence, incidence and risk factors of herpes simplex virus type 2 infection among pregnant Zimbabwean women followed up nine months after childbirth.

BACKGROUND: Herpes simplex virus type 2 (HSV-2) is the leading cause of genital ulcer disease worldwide. The virus can be transmitted to neonates and there are scarce data regarding incidence of HSV-2 among women in pregnancy and after childbirth. The aim of this study is to measure the incidence and risk factors for HSV-2 infection in women followed for 9 months after childbirth. METHODS: Pregnant women were consecutively enrolled late in pregnancy and followed at six weeks, four and nine months after childbirth. Stored samples were tested for HSV-2 at baseline and again at nine months after childbirth and HSV-2 seropositive samples at nine months after childbirth (seroconverters) were tested retrospectively to identify the seroconversion point. RESULTS: One hundred and seventy-three (50.9%) of the 340 consecutively enrolled pregnant women were HSV-2 seronegative at baseline. HSV-2 incidence rate during the 10 months follow up was 9.7 (95% CI 5.4-14.4)/100 and 18.8 (95% CI 13.9-26.1)/100 person years at risk (PYAR) at four months and nine months after childbirth respectively. Analysis restricted to women reporting sexual activity yielded higher incidence rates. The prevalence of HSV-2 amongst the HIV-1 seropositive was 89.3%. Risk factors associated with HSV-2 seropositivity were having other sexual partners in past 12 months (Prevalence Risk Ratio (PRR) 1.8 (95% CI 1.4-2.4) and presence of Trichomonas vaginalis (PRR 1.7 95% CI 1.4-2.1). Polygamy (Incidence Rate Ratio (IRR) 4.4, 95% CI 1.9-10.6) and young age at sexual debut (IRR 3.6, 95% CI 1.6-8.3) were associated with primary HSV-2 infection during the 10 months follow up. CONCLUSIONS: Incidence of HSV-2 after childbirth is high and the period between late pregnancy and six weeks after childbirth needs to be targeted for prevention of primary HSV-2 infection to avert possible neonatal infections.

Timing of mother-to-child transmission of HIV-1 and infant mortality in the first 6 months of life in Harare, Zimbabwe.

OBJECTIVES: To examine the risks of intra-uterine (IU), intra- and early post-partum (IP/ePP) and late post-partum (LPP) mother-to-child transmission (MTCT) of HIV-1 and infant mortality in the first 6 months of life. METHODS: Whole blood was collected in ethylenediaminetetra-acetic acid at birth, 6 weeks, 3 and 6 months from 996 infants born to HIV-1 seropositive mothers. Polymerase chain reaction using Roche DNA amplification assay, version 1.5 (Roche Diagnostics Incorporation, Alameda, California, USA) was used to determine timing of MTCT. Logistic regression models determined risk factors for HIV-1 transmission and survival analyses examined mortality by timing of transmission. RESULTS: Two hundred and forty-nine mothers (30.7%) transmitted HIV-1 infection to their infants by 6 months of age. Eighty-nine infants [9.4%; 95% confidence interval (CI), 7.7-11.5], 104 infants (16.0%; 95% CI, 10.8-21.2) and 21 infants (5.3%; 95% CI, 1.6-12.2) were infected IU, IP/ePP and LPP respectively. Low maternal CD4 cell count and arm circumference were risk factors for IP/ePP transmission. Infant mortality was higher among infected infants than uninfected (P < 0.001, log rank test). Timing of infection, birth weight and maternal CD4 cell counts were important factors in predicting infant death. CONCLUSION: In the first 6 months of life, IU and IP/ePP transmission contributed more than three-quarters of the 30.7% MTCT. Our data, in addition to serving as a historical comparison, may be useful in designing and evaluating the efficacy of short course antiretroviral trials aimed at reducing MTCT in developing countries.