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Int J STD AIDS OnlineFirst, published on December 12, 2014 as doi:10.1177/0956462414563776
Original research article
Prevalence of thyroid dysfunction and its correlation with CD4 count in newly diagnosed HIV-positive adults – a cross-sectional study
International Journal of STD & AIDS 0(0) 1–6 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0956462414563776 std.sagepub.com
Nishanth Dev1, Ratnakar Sahoo2, Bindu Kulshreshtha2, A K Gadpayle2 and S C Sharma2
Summary Prevalence of subclinical hypothyroidism in HIV-positive patients is reported to be high in those with severe immune deficiency. However, there is paucity of literature in newly diagnosed HIV-positive population. Our aim was to estimate the prevalence of thyroid dysfunction and study its correlation with CD4 count in this population. In this cross-sectional study, patients presenting to the anti-retro viral therapy clinic were screened for thyroid function tests, including thyroid stimulating hormone, free triiodothyronine, free thyroxine, and anti-thyroid peroxidase antibody levels at the time of diagnosis. Two hundred and twenty five HIV-positive and an equal number of healthy volunteers were enrolled. The mean (SD) CD4 count in the study group was 147.1 (84) and 70.7% had advanced immune deficiency with CD4 count 18 years of age presenting to the anti-retroviral therapy clinic and not on HAART at the time of enrollment were included in the study group. Similar number of age- and gender–matched HIV-negative healthy volunteers who were either relatives of the study population or of those admitted in the general medicine wards were included in the comparison group. We excluded those with history of thyroid illness, clinically evident thyroid enlargement or signs of thyroid disease, those with abnormal liver function, deranged kidney function, and known diabetic patients. We also excluded those on medications which influence the thyroid function parameters like rifampicin, steroids, amiodarone, anti-epileptics and anti-fungal drugs. The exclusion criteria were carefully looked for in both the study as well as control groups. The eligible subjects were enrolled after obtaining informed consent. The study was approved by the Institutional Ethics Committee.
A detailed clinical examination was also performed and the variables recorded in a pre-structured proforma. The subjects underwent routine investigations which included the complete haemogram, liver function tests, kidney function tests, lipid profile, Hepatitis B antigen, Hepatitis C antibody, venereal disease research laboratory, chest X-ray, sonography of abdomen and CD4 count. We used enzyme linked immunosorbent assay (ELISA) test for diagnosis of HIV-positive patients using three different kits, namely combs AIDS, Retro check and micro ELISA. Patients included were HIVpositive by all three kits. CD4 count was determined using Becton–Dickinson FACS flow cytometer. A single fasting blood sample was drawn in enrolled patients and sent to laboratory for assessment of thyroid function parameters which included TSH, FT3, FT4 and anti-TPO antibody. FT4 and FT3 levels were measured by chemiluminescent enzyme immunoassay using VITROS immunodiagnostic products. TSH level was measured by VITROS reagent system and an immunometric immunoassay technique. Anti-TPO antibody levels were measured by VITROS immunodiagnostic products based on chemiluminescence immunoassay principle. TSH value between 0.5 and 5.0 mU/ml, FT3 level between 2.0 and 4.4 pg/dl, FT4 level between 0.7 and 2.0 ng/dl and anti-TPO antibody level up to 50 IU/ml were taken as normal values. The definitions used for defining various thyroid abnormalities are provided in Appendix 1 (supplemental digital content).
Sample size estimation The prevalence of thyroid dysfunction in HIV-positive adults is reported to range between 10 and 40%.4–7 With a precision of 5% and design effect of 1, we needed to enroll 220 patients for achieving a confidence level of 95%.
Statistical analysis Objectives Our objectives were (1) to evaluate the prevalence of thyroid dysfunction in treatment naı¨ ve HIV-positive adults and (2) to study its correlation with the CD4 counts.
Study protocol Once enrolled, a detailed history including risk factors for mode of possible transmission of HIV (heterosexual, homosexual, intravenous drug abuser and blood transfusion), duration of illness, history suggestive of any opportunistic infections and symptoms of any kind of endocrine dysfunction was carefully elucidated.
Data was analysed using statistical package STATA version 11.0 (College Station, TX: Stata Corp LP). Continuous variables are presented as mean (SD), or median (IQR) as appropriate. Categorical variables are presented as absolute numbers (%). Continuous variables were compared using either independent Student’s t-test or Wilcoxon rank-sum test (based on the distribution of the data). Categorical data were compared using Chi squared test or Fischer’s exact test as appropriate. The correlation between CD4 counts and thyroid functions was assessed by Pearson’s correlation coefficient and linear regression analysis. We also performed multivariate linear regression to adjust for confounders such as age, gender, IV
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Dev et al.
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drug abuse, and opportunistic infections that we thought could affect the results of univariate regression.
Results Baseline characteristics The baseline characteristics of the enrolled patients are described in Table 1. A total of 225 HIV-positive patients and 225 healthy volunteers eligible for the
Table 1. Baseline characteristics of the study population. Variables
HIV positive
HIV negative
p value
Gender Men 154 (68.4%) 153 (68%) Women 71 (31.6%) 72 (32%) 0.92 Age (years) [mean (SD)] 36.6 (10.2) 36.4 (11.6) 0.87 Mode of transmission – Heterosexual 201 (89.3%) – Homosexual 03 (1.3%) – Intravenous drug abuse 15 (6.7%) – Blood transfusion 06 (2.7%) – Co-infections – Pulmonary tuberculosis 21 (9.33%) – Syphilis 04 (1.77%) – CD4 count – 500/mL – Thyroid function tests [mean (SD)] TSH 6.2 (2.4) 3.4 (2.2)
