CKD-MBD PROFILE IN DIABETIC AND NON-DIABETIC CHRONIC KIDNEY DISEASE ON NON-DIALYSIS STAGE AND ITS CONNECTION WITH CARDIOVASCULAR HEALTH

CKD–mineral and bone disorder (MBD)  evolved to acknowledge its systemic consequences and damage to multiple organs that extends beyond bone, primarily vascular calcification (VC). several biochemical abnormalities have been related to clinically significant VC. It is not clear which aspect of bone pathology is most closely associated with VC. Here we aimed to investigate bone metabolic parameters in diabetic and non-diabetic group of chronic kidney disease patients between stages 3 to 5 and to assess its correlation with cardiovascular finding by measuring carotid intimal media thickness (CIMT) and coronary calcium scan score. 

The study is a cross sectional observational study conducted in a tertiary care centre at Department of Nephrology, Narayana Hrudayalaya hospitals, Bangalore between February 2020 to July 2021. All Patients more than 18 years or older who were diagnosed with chronic kidney disease stage 3 to 5, not on any type of renal replacement therapy included in the study. Total of 158 patients were enrolled and divided into two group diabetic and non-diabetic kidney disease with each having 79 subjects. Those who were critically ill and under intensive care unit were excluded in the study. Institutional ethics committee approval was obtained prior to the study. Baseline characteristics and data were recorded at entry and divided into two observational study groups according to native kidney disease into diabetic and non-diabetic kidney disease. Current medications were noted. Investigations were done as a part of routine CKD-MBD work-up, electrocardiogram, 2D Echo – cardiography, neck vessel doppler to look for carotid intimal media thickness and coronary calcium scan were done as per the standard of care.

The maximum number of subjects were between 51 – 60 year of age 43/158(27.2%) and mean age was 55.02 years and there were 158 patients, of which 117 (74.1 %) were males and 41 (25.9 %) were females. In both the group, maximum patient were in CKD stage 5, 39(49.4%) in diabetic and 37(46.9%) in non-diabetic group. Mean value of serum vitamin D, serum PTH and serum ALP were more in diabetic group whereas, the mean value of serum calcium and phosphorus were more in the non-diabetic group of patients. There was no statistical significance between the two groups. Most of patients in diabetic group had calcium score between 101 to 400 (30.4%) and 401 to 1000(25.3%) whereas approximately (62 % ) patients in non-diabetic group had zero CT coronary score. The P value was found significant (p value of 0.003). Most of patients in both group had normal carotid intimal media thickness, mildly raised thickness of carotid intimal media was noted more in diabetic CKD (38%) patients. No significant difference in incidence of cardiac events in both the groups. The number of cardiac events were more in diabetic groups. Hyperparathyroidism had significant correlation with raised carotid intimal media thickness in diabetic patients (pValue 0.002*). Hypoalbuminemia was significantly correlated with poor LV function in patients with non- diabetic group. Serum calcium ( p value 0.025*) and serum PTH level ( p value 0.027*) had significant correlation with CT coronary score in diabetic group of patients. 

Hypocalcemia, hyperparathyroidism and vitamin D deficiency were seen commonly in most of the patients. These finding suggests high bone turn over pattern of CKD- MBD. there is no significant difference in the calcium, phosphorus, PTH, vitamin D and ALP values between the diabetic and the non-diabetic group of patients. The presence or absence of diabetes, also does not significantly alter the bone metabolism in CKD. We consider CT coronary calcium score and increased CIMT as surrogate markers for systemic vascular calcification which showed statistically significant association in diabetic group of patients. Hypoalbuminaemia is also an important predictor for cardiovascular morbidity and mortality and was significantly associated with poor LV function in non diabetic patient group. The central tenets of treatment of CKD-MBD are correction of altered Ca, P with calcium supplements, phosphate binders. We conclude that all CKD patients with CACS >0 and 10 year atherosclerotic cardiovascular disease (ASCVD) risk >7.5% to 20% according to the American Heart Association/American College of Cardiology guideline (2018), should be initiated on statins and antiplatelet drugs if any cardiac events ensues.