Analysis Of Associated Factors With Hypoparathyroidism In Maintenance Hemodialysis Patients

Objective Secondary hyperparathyroidism had got better control nowadays with the progression of treatment, but the incidence of hypoparathyroidism was growing. This paper was to study the prevalence and associated factors with hypoparathyroidism in maintenance hemodialysis patients in one single medical center. The goal was to analyse the reason of low parathyroid hormone level and the risk factors related to adynamic bone disease, to determine the high-risk groups and to guide clinical treatment.Methods A cross-section study was performed. A total of 71 eligible participants undergoing hemodialysis treatment for more than three months in our hemodialysis center in the second hospital of shandong university from January 2013 to December 2013 were recruited in the study. Sweden jinbao AK96 machine and polyether sulfone membrane PES-130DS dialyser produced by Japanese company were used in all the patients, effective membrane area was 1.3m2. Calcium concentration of dialysate was 1.5mmol/L, potassium 2mmol/L, sodium 140mmol/L, bicarbonate 30mmol/L. All patients used arteriovenous fistula or deep vein pipe for dialysis, dialysis fluid flow were set 500 ml/min, blood flow 200～280 ml/min according to the patients’ weight, temperature 36 to 37℃. All patients dialysed 2-3 times a week (8～12 h/week),4h each dialysis according to the residual kidney function.Statistics of all the cases of general materials, including gender, age, dry weight, height, dialysis duration, primary disease, dry weight was used to calculate body mass index (BMI). Basic dialysis parameters including blood flow, vascular access, ultrafiltration, dialysis time, heart rate, blood pressure before dialysis, mean arterial pressure (MAP), weekly frequency of dialysis, frequency of HDF in a year were recorded. Key laboratory indicators included:hemoglobin (HB), albumin (ALB), urea nitrogen (BUN), serum creatinine, alkaline phosphatase (AKP), blood calcium, phosphorus, β2microglobulin ((32MG) and intact parathyroid hormone (iPTH) levels. Blood test was made at the end of dialysis by reducing blood flow to 50 ml/min for 15 secend. Test indexes included urea nitrogen, serum creatinine.RIA method was applied to determine the blood level of intact parathyroid hormone (iPTH), a diagnosis of hypoparathyroidism was made when arithmetic mean of iPTH< 100 ng/L according to the results of two iPTH measurements (the interval between the first and the second test was at least 3 months). All the patients were divided into the lower parathyroid hormone level group (LPTH group) and the normal or higher parathyroid hormone level group (non-LPTH group) according to the intact parathyroid hormone(iPTH) level. The prevalence of hypoparathyroidism was calculated, and the associated factors of hypoparathyroidism were investigated through Logistic regression analysis.ResultsParticipants included 71 patients, the primary diseases included 28 cases (39.4%) of chronic glomerulonephritis,24 cases (33.8%) of diabetic nephropathy,11 cases (15.5%) of hypertension,4 cases (5.6%) of polycystic kidney disease,2 cases (2.8%) of chronic interstitial nephritis and 2 cases of unknown causes (2.8%). Chronic glomerulonephritis and diabetic nephropathy were the most common original diseases in my center. The LPTH group included 28 cases (39.4%), the level of iPTH was on average 77.34±46.07ng/L. The non-LPTH group included 43 cases (60.6%), iPTH levels was on average 803.16±439.05ng/L. Comparative difference was statistically significant between the two groups (P=0.001). The prevalence of hypoparathyroidism was 39.4%.The LPTH group included 16 cases of diabetic nephropathy, accounting for 57.1%, far higher than the 18.6% of the non-LPTH group. Dialysis duration was 45.09±32.62 months on average in the LPTH group,17.61±23.45months on average in the non-LPTH group. ALB was 30.26±5.50 g/L on average in the LPTH group, 38.84±3.71g/L on average in the non-LPTH group. AKP was 80.68±62.95U/L on average in the LPTH group,169.31±216.59U/L on average in the non-LPTH group. The corrected blood calcium was 8.95±0.96mg/dL on average in the LPTH group, 8.24±1.09mg/dL on average in the non-LPTH group. Comparative difference was statistically significant between the two groups.Compared with the non-LPTH group, the patients of the LPTH group were more older, had longer dialysis duration, the primary disease mostly diabetic nephropathy, lower ALB and AKP, higher calcium levels. There was no statistical difference in BMI, dialysis frequency, number of HDF, heart rate, MAP, Kt/V, HB, blood phosphorus, the calcium-phosphorus product and the β2MG levels between the two groups.Logistic regression analysis demonstrated that age, long vintage, diabetic nephropathy, lower ALB and AKP and hypercalcemia were independent influencing factors of LPTH.Conclusions The prevalence of hypoparathyroidism is quite high in MHD patients. Chronic glomerulonephritis and diabetic nephropathy were the most common primary diseases in patients receiving hemodialysis. Age, time on dialysis, primary disease, malnutrition and index of calcium and phosphorus metabolism of parathyroid hormone levels were independent factors of hypoparathyroidism.