**2.3 Variables, data collection, and sample analyses**

With the help of a questionnaire, demographic, anthropometric, and other relevant data were obtained from the themes. The purpose of the study was explained to the themes. The age, gender, place of origin, and domicile were obtained. Height was measured and recorded in meter (m). Weight was measured employing a weighing scale. Body mass index was taken as the ratio of weight/height2 (kg/m2 ).

The study participants were clearly instructed on the way to collect 24-hour urine sample. At the conclusion of the 24-hour urine sample collection, blood samples, and daytime random spot urine samples were collected. Spot urine creatinine, spot urine osmolality, and spot urine protein from the random spot urine samples were performed. Also from the 24-hour urine samples collected, 24-hour urine protein, 24-hour urine creatinine, and 24-hour urine osmolality were performed. Serum creatinine was performed on the blood samples collected. Freezing point depression assay was used to determine osmolality, protein by photometric method, and creatinine by modified Jaffe's method. Creatinine clearance and spot urine creatinine/osmolality ratio were calculated. HIV screening and confirmatory tests, fasting serum lipid profile, CD4 cell count, and hemoglobin were performed.

### **2.4 Potential risk variables analyzed**

The potential associated factors of dilute and concentrated urine evaluated were CD4 cells, spot urine protein, spot urine osmolality, 24-hour urine osmolality, 24-hour urine protein, spot urine creatinine/osmolality ratio, creatinine clearance, serum cholesterol, serum low-density lipoprotein cholesterol, serum triglyceride, and serum high-density lipoprotein cholesterol.

## **2.5 Statistical analyses**

The data were analyzed using SPSS version 17.0 (SPSS Inc. Chicago, IL, USA). The distribution and characterization of clinical and laboratory variables within the study participants with different levels of 24-hour urine creatinine were analyzed using cross-tabulation, whereas statistical significance of association of these variables with 24-hour urine creatinine levels was evaluated using Student's t-test. Correlation statistics were used to determine the association of those variables with concentrated urine on the one hand and with dilute urine on the other hand. The strength of variables to predict dilute urine and concentrated urine was determined using multivariate linear regression analyses. P < 0.05 was taken as statistically significant.

### **2.6 Definition of terms**

Normal urine creatinine: 24-hour urine creatinine 300–3000 mg. Low urine creatinine or dilute urine: 24-hour urine creatinine <300 mg. High urine creatinine or concentrated urine: 24-hour urine creatinine >3000 mg.
