Pattern of Bone Mineral Density at Optimal Skeletal Measurement Site among Patients on Maintenance Hemodialysis
Author(s): Dr. Madhabi Karmaker, Dr. Samira Khatun, Dr. Farnaz Nobi, Dr. Shanjida Sultana Juthy, Dr. Khaleda Akhter
Background: Chronic Kidney Disease (CKD) and Mineral-Bone Disorders (MBD) are important health problems. According to the KDIGO CKD-MBD guideline, bone loss and fracture risks are higher in CKD patients than in age-matched controls throughout all the stages, with the highest incidence among dialysis patients. Bone densitometry (BMD) is a preferred method for diagnosing osteopenia/osteoporosis. Interpreting bone densitometry in End-Stage Renal Disease (ESRD) patients requires careful assessment.
Aim of the study: To determine the pattern of bone mineral density in optimal skeletal measurement sites in patients of both genders on maintenance hemodialysis using the DEXA method.
Methods: This cross-sectional study was carried out in the Nephrology department of Dhaka Medical College Hospital from October 2020 to October 2021. A total of 60 ESRD patients (Group A, 30 male and Group B, 30 female patients) fulfilling the selection criteria were included in this study. All the subjects were evaluated clinically, and relevant data were recorded in a structured questionnaire. Bone Mineral Densitometry (BMD) test was done in every study population. Laboratory data was collected after measuring serum calcium, phosphate and iPTH levels. Statistical analysis of the clinical, densitometric and laboratory data was obtained using window-based computer software devised with Statistical Packages for Social Sciences (SPSS-23). Results were expressed in various tables.
Results: The mean age of group A (male) was 43.24±10.92 years, and group B (female) was 41±12.6 years. The mean BMI was significantly higher in females (27.19±5.98 kg/m2) than in males (23.71±4.42 kg/m2). The mean duration of dialysis was higher in males than females. The mean total BMD value expressed as gm/cm2 was almost similar, 1.04±0.22 (g/ cm2) in group A and 1.05±0.18 (g/cm2) in group B, and no statistically significant (p>0.05) difference was observed between two groups. Considering conventional BMD sites (lumbar spine, left hip), 28(46.7%) patients had normal bone mass, 22(36.7%) patients had osteopenia, out of which 13(43.3%) were male and 9(30.0%) were female. Total 10(16.6%) patients had osteoporosis, out of which 4(13.4%) male and 6(20.0%) female. The difference between the two groups was insignificant (p>0.05). While considering left forearm BMD, it was found that 33.3% of males had osteopenia and 66.7 % of males had osteoporosis; on the other hand, in females, 20 % had osteopenia, and 53 % had osteoporosis. Regarding the skeletal site, the mean Total T score differences in the left hip (neck, G.T, inter) were statistically significant (p<0.05) between males and females. According to the Z score, low bone density was also higher in males; the prevalence of low bone density (Z score <-1) was between 20 and 40 %, while 13.3% to 20% in females. Again, the Z score below the expected range for age (Z score <-2.0) was between 13.3% to 80 % in males and 13.3% to 40 % in females. The mean calcium and phosphate level difference was not statistically significant between male and female patients, but the iPTH level was higher in male patients. Different Correlations between BMD of measurement sites and laboratory and clinical parameters, expressed as a coefficient of correlation (r), were also found in male and female patients, with better correlation of skeletal sites in female patients.
Conclusion: Regardless of limitations, this study showed reduced bone mass in HD patients and different reductions of bone mass in different skeletal sites (both central and peripheral) in male and female patients.