Prevalence and risk factors for loss of bone mineral density in male Japanese patients with HIV.

To the Editors: As the mortality of HIV-infected individuals was improved by combination antiretroviral therapy (cART), opportunistic infections were replaced by long-term complications including loss of bone mineral density (BMD). It was first reported in 1999 and has emerged in the last decade and has probably placed HIV-infected individuals at higher risk of bone fractures. The causes are considered to be multifactorial and include HIV infection itself, body mass index (BMI), estimated glomerular filtration rate (eGFR), testosterone level, and hepatitis coinfection. Some articles link the use of protease inhibitors and the tenofovir (TDF) with lower BMD. Most of the articles associated with BMD loss in HIV-infected patients have been reported from North America, Europe, and Oceania. Accordingly, the BMD research on HIV-infected Asians is underrepresented. In this work, we focused on male Japanese HIV-infected patients and studied the prevalence and severity of BMD loss among them and attempted to determine clinical factors related to BMD loss. Forty male Japanese HIV-infected individuals aged from 21 to 70 years who visited the Teikyo University Hospital were enrolled in this study. This study was approved by the ethical committee of the Teikyo University School of Medicine, and the patients gave written informed consent. The patients underwent BMD analyses from March 2010 to February 2012 with the same dual energy X-ray absorptiometry scan (Discovery SI, Hologic Inc, Bedford, MA). Thirty-nine patients were analyzed in both the lumbar spines and bilateral femoral necks, whereas 1 patient was limited to the bilateral femoral necks. The BMD data of the lumbar spines and the smaller BMD value of the femoral necks were employed to calculate T-scores that were calculated as comparison with young normal reference value expressed as SD units. Osteopenia was defined as a T-score of between −1 and −2.5SD, and osteoporosis was defined as that of $ −2.5 negative score following the World Health Organization classification. Clinical factors were collected including age, height, body weight, BMI, smoking status, use of corticosteroid, CD4 cell counts, durations of cART, medication of nucleoside/nucleotide reverse transcriptase inhibitors, serum creatinine, bone alkaline phosphatase (BAP), eGFR, serum, and urine N-terminal telopeptide (NTx). The eGFR for Japanese male patients were calculated by 194 · serum creatinine−1.094 · age−0.287 (mL/min per 1.73 m2). To determine the high-risk groups, statistical differences of T-scores were calculated by using Wilcoxon signed ranks or Kruskal–Wallis test with the post hoc comparisons by the Dunnett test. The correlations between T-scores and each variable were examined by a linear regression employing the method of least squares. A multiple regression analysis was conducted by employing these variables with a P value ,0.1 to predict BMD loss. All the analyses were performed by JMP version 8.0.1 (SAS Institute Inc, United States). The median age of the patients was 39 years. Their median height and body weight were 169.3 cm and 65.0 kg, respectively. Twenty-three patients were #170 cm, and 14 were ,60 kg. The median CD4 count was 396/mL. Twenty-seven were on cART, and median duration of cART was 2.9 years. Five have been continued on cART for . 10 years. Twelve out of 27 took TDF/emtricitabine (FTC), and 13 took abacavir/lamivudine (3TC). The median and interquartile ranges of BMD and T-scores in the lumbar spines and the femoral necks are summarized in Table 1. The median T-scores in the lumbar spines and the femoral necks were −0.8 and −1.2, respectively. The T-scores of the femoral necks were significantly lower than those of the lumbar spines (P = 0.0461). By employing the T-scores in the lumbar spines, the prevalence of osteopenia and osteoporosis was found to be 43.6% and 5.1%, respectively, and these percentages rose to 47.5% and 7.5%, respectively, if the least T-scores in the femoral necks were used. Moreover, the number (and percentage) of patients with osteopenia and osteoporosis were 21 (52.5%) and 4 (10%), respectively, in at least 1 of the T-score measured in the lumbar spines or in the femoral necks. Subgroup analyses of patients’ baseline characteristics revealed that the group of patients aged 50 years or older was the only group that showed significantly lower T-scores of the lumbar spines. In contrast, high-risk groups that showed significantly lower T-scores of the femoral necks were patients aged 40 years or older, #170 cm in height, weighed #60 kg, those on cART, particularly those continuing cART for $10 years. There were no significant differences between the 2 groups divided based on the medication of nucleotide reverse transcriptase inhibitors or use of corticosteroid.