**Abstract**

This study assessed urine creatinine in spot and 24-hour samples in HIV and non-HIV population. We categorized dilute urine as a 24-hour urine creatinine <300 mg, concentrated urine as a 24-hour urine creatinine >3000 mg, and normal urine as a 24-hour urine creatinine 300–3000 mg. Association of variables with creatinine was evaluated. In HIV subjects, the mean spot urine creatinine was 137.21 ± 98.47 mg/dl and a 24-hour urine creatinine was 1507 ± 781 mg. The prevalence of dilute urine was 0.5%, normal urine 93.1%, and concentrated urine 6.4%. 20-hour urine creatinine was associated with serum LDL, and HDL. Concentrated urine was correlated with a 24-hour urine osmolality (r = 0.95), serum HDL (r = −0.73), CD4 cells count (r = −0.71), and BMI (r = 0.74). Dyslipidemia was common in HIV subjects with concentrated urine. In non-HIV subjects, the mean spot urine creatinine was 148 ± 167 mg/dl and the 24-hour urine creatinine was 1203 ± 316 mg. The 24-hour urine creatinine was within the normal range. The spot urine creatinine significantly correlated with BMI, spot urine protein, spot urine osmolality, 24-hour urine protein, 24-hour urine creatinine, serum creatinine, serum cholesterol, and serum LDL. Conversely, the 24-hour urine creatinine significantly correlated with 24-hour urine volume, serum creatinine, and serum cholesterol. The spot urine protein and 24-hour urine protein were predictors of spot urine creatinine. Serum creatinine was a predictor of 24-hour urine creatinine. Proteinuric renal abnormalities were common.

**Keywords:** HIV, urine creatinine, spot urine creatinine, 24-hour urine creatinine, CD4 cell count, concentrated urine, dilute urine, abnormal weight, dyslipidemia, proteinuria

### **1. Introduction**

#### **1.1 Impact of HIV**

Human immunodeficiency virus infection is a world healthcare burden with sub-Saharan Africa as a geographic area accounting for about 70% of HIV-infected persons [1]. In Nigeria the prevalence of HIV is 3.7% [1]. HIV infection directly or indirectly affects most organs of the body [2]. In like manner, tons of physiological responses are also altered by HIV disease process [3–5].

#### **1.2 Factors which may influence creatinine**

Creatinine is produced by the muscles, degraded within the liver, and efficiently excreted by the kidney at a rate that is not only constant but is additionally modulated by weight, gender, and age [6].

Many environmental, physiologic, and disease conditions may impact on daily urine creatinine excretion. Excretion of creatinine is further altered by exogenous substances such as cocaine and heavy metals which include arsenic and cadmium seen within the bioenvironment related to environmental pollution. Others include meat consumption and medications such as cimetidine and trimethoprim. Consequently, urine creatinine is employed in monitoring bioenvironmental pollutants and substance use [7–9].

#### **1.3 Variability of daily urine creatinine**

There is high variability of the values of daily urine creatinine excretion in normal healthy state [10]. Impaired renal function usually results in poor renal secretion of creatinine in urine; urine creatinine decreases as renal function impairment increases [11].

#### **1.4 Identified factors of high and low 24-hour urine creatinine**

Studies have identified some associated factors of high 24-hour urine creatinine or concentrated urine. They include age, sex, race, body mass index, hypertension, water intake, and blood osmolality [12]. At the other pole, low 24-hour urine creatinine or dilute urine was reported to be associated with glomerular filtration rate, an older age, diabetes, and lower levels of body mass index, proteinuria, and protein intake [11]. Another important use of urine creatinine is for evaluating the completeness of 24-hour urine sample collection [13].

#### **1.5 A necessity for routine assessment of urine creatinine in HIV and non-HIV subjects**

Studies are sparse on urine creatinine in HIV and non-HIV subjects originating from Nigeria. We have, therefore, launched to evaluate urine creatinine and factors which influence low and high urine creatinine in these groups of subjects.

#### **2. Methods**

#### **2.1 Study location and population**

This was a cross-sectional study, comprising 375 HIV-positive subjects and 136 subjects recruited from an HIV clinic and also the general outpatient clinic, respectively, of the Federal Medical Centre, Owerri, Nigeria. The study was disbursed and carried out between April and August 2011. The standards for inclusion were HIV-positive status for the HIV subjects and HIV-negative status for the non-HIV participants. For both groups of subjects, another criterion was age range of 16–65 years. The themes excluded from the study were people who had adrenal, pituitary, and renal diseases, terminal illness, and pregnancy. For the non-HIV subjects, the inclusion criteria were similar, but those with HIV-positive status were excluded.
