Prevalence and risk factors for secondary hyperparathyroidism (SHPT) in patients undergoing bariatric surgery.

INTRODUCTION: Secondary hyperparathyroidism (SHPT) after bariatric surgery has significant adverse implications for bone metabolism, increasing the risk for osteoporosis and fracture. Our aim was to characterize prevalence and identify risk factors for SHPT in bariatric surgery patients. METHODS: We performed a single-institution, retrospective chart review of patients who underwent bariatric surgery from June 2017 through December 2021. Demographic and clinical data were collected, including serum parathyroid hormone, calcium, and vitamin D3 at enrollment and 3, 6, and 12-months postoperatively. Chi-square or Fisher's exact tests were used to analyze categorical data and Mann-Whitney U test for continuous data. Multivariable analysis using binomial logistic regression assessed risk factors for SHPT. P-values ≤ 0.05 were considered significant. RESULTS: 350 patients were analyzed. SHPT prevalence at any time point was 72.9%. 65.8% had SHPT at enrollment; 45.9% resolved with intensive vitamin supplementation; and 19.7% had recurrent SHPT. New-onset SHPT occurred in 8.6%. Persistent SHPT was present in 42.4% at 1-year. Baseline SHPT correlated with black race and T2DM. SHPT at any time point correlated with T2DM and higher baseline BMI. 1-year SHPT correlated with RYGB, depression, and longer time in program. SHPT was not correlated with %TBWL at any time point. In patients with SHPT, vitamin D3 deficiency prevalence was significantly higher at baseline (77.0%) compared to all post-bariatric time points (16.7%, 17.3%, and 23.1%; P < 0.0001). CONCLUSIONS: SHPT is highly prevalent in patients with obesity seeking weight loss surgery. 42% had persistent SHPT at 1-year despite appropriate vitamin supplementation. Current vitamin D3 and calcium supplementation protocols may not effectively prevent SHPT in many post-bariatric patients. Low prevalence of concomitant vitamin D3 deficiency with SHPT after bariatric surgery suggests that there may be alternative mechanisms in this population. Further studies are needed to develop effective treatment strategies to mitigate the adverse effects of bariatric surgery on bone metabolism.

Prevalence and associated factors of secondary hyperparathyroidism after Roux-en-Y gastric bypass: A meta-analysis.

This study aimed to investigate the prevalence and factors associated with secondary hyperparathyroidism (SHPT) after Roux-en-Y gastric bypass (RYGB). We searched PubMed, EMBASE, and CENTRAL for relevant studies using search terms gastric bypass, RYGB and hyperparathyroidism. Thirty-four cohort studies with 4331 patients were incorporated into the final meta-analysis. Overall estimates of the prevalence of SHPT following RYGB were 39%. Subgroup analyses indicated the pooled prevalences of SHPT were 25%, 42%, 48%, and 54% for ≤1 year, >1 and ≤5 years, >5 and ≤10 years, and >10 years, respectively, after RYGB. Meta-regression showed that SHPT occurred was positively related to follow-up durations (p = 0.001). Additionally, SHPT prevalence was higher in studies in which calcium and vitamin D supplementation were considered inadequate than in those which were adequate (p = 0.002). SHPT is highly prevalent in individuals with obesity after RYGB. It seems to progress with time after surgery. Routine calcium and vitamin D supplementation post-RYGB together with targeted treatment of vitamin D deficiency, reasonable adjustment of the doses of supplementation with regular follow-up, and improved patient compliance, as well as long-term screening, are necessary to prevent the development of SHPT.

Secondary Hyperparathyroidism Among Bariatric Patients: Unraveling the Prevalence of an Overlooked Foe.

INTRODUCTION: Bariatric surgery (BS) is the most effective therapeutic approach to obesity. It is associated with great gastrointestinal anatomic changes, predisposing the patients to altered nutrient absorption that impacts phosphocalcium metabolism. This study aimed to clarify the prevalence of secondary hyperparathyroidism (SHPT) and its predictors in patients submitted to BS. METHODS: Retrospective study of 1431 patients who underwent metabolic surgery between January 2010 and June 2017 and who were followed for at least 1 year. We compared the clinical and biochemical characteristics of patients with and without secondary hyperparathyroidism (considering SHPT a PTH ˃ 69 pg/mL). Two different analyses were performed: (1) paired analysis of participants before and 1 year after surgery (N = 441); (2) Cross sectional analysis of participants submitted to bariatric surgery before (N = 441), 1 year after (N = 1431) and 4 years after surgery (N = 333). Multiple logistic regression models were used to evaluate possible predictors of SHPT after BS. RESULTS: The overall prevalence of SHPT was 24.9% before surgery, 11.2% 1 year after surgery and 21.3% 4 years after surgery. Patients submitted to LAGB had the highest prevalence of SHPT 1 year after surgery (19.4%; vs RYGB, 12.8%, vs SG, 5.3%). Four years after surgery, RYGB had the highest prevalence of SHPT (27.0%), followed by LAGB (13.2%) and SG (6.9%). Higher body mass index and age, decreased levels of vitamin D and RYGB seem to be independent predictors of SHPT 1 year after surgery. The only independent predictor of SHPT 4 years after surgery was RYGB. CONCLUSION: The prevalence of SHPT is higher before and 4 years after BS than 1 year after surgery. This fact raises some questions about the efficacy of the implemented follow-up plans of vitamin D supplementation on the long term, mainly among patients submitted to RYGB.

Endocrine disorders after heart transplantation: national cohort study.

BACKGROUND: Endocrine disorders in patients after heart transplantation (HT) remain understudied. We aimed to assess endocrine profiles and management of HT recipients in the early post- transplant period. METHODS: We conducted a retrospective cohort study on 123 consecutive HT recipients in the Advanced Heart Failure and Transplantation Programme between 2009 and 2018. All recipients had per-protocol endocrine follow-up within the first postoperative year. The median time to first post-transplant endocrine follow-up was 3 months (IQR 2-4). We assessed the incidence of vitamin D deficiency, bone mineral density, history of low energy fractures, hypogonadism in male recipients, posttransplant diabetes mellitus, and thyroid and parathyroid function. RESULTS: We enrolled 22 women and 101 men of median age 57 years (IQR 50-63). Post-transplant diabetes mellitus developed in 14 patients (11.4%). 18 of 25 patients (14.6%) with preexisting type 2 diabetes mellitus required intensification of antidiabetic therapy. 38 male patients (40.4%) had hypogonadism. 5 patients (4.6%) were hypothyroid and 10 (9.3%) latent hyperthyroid. Secondary hyperparathyroidism was present in 19 (17.3%), 25-hydroxyvitamin D deficiency in 64 (54.7%) of patients. Osteoporosis was present in 26 (21.1%), osteopenia in 59 (48.0%) patients. 47 vertebral fractures, 3 hip and 1 humerus fractures occurred in 21 patients. Most of the patients had coincidence of two or three disorders, while less than 5% did not have any endocrine irregularities. All patients received calcium and vitamin D supplements. Forty-six patients (37.4%) were treated with zoledronic acid, 12 (9.8%) with oral bisphosphonates. Two patients were treated with teriparatide. CONCLUSIONS: The prevalence of multiple endocrine disorders early after heart transplantation is high. Assessment and management of increased fracture risk and all other potentially affected endocrine axes should be considered as a standard of care in this early period.

Biochemical spectrum of parathyroid disorders diagnosed at a tertiary care setting.

OBJECTIVE: To determine the clinical and biochemical pattern of parathyroid disorders in a tertiary care setting.. METHODS: The cross-sectional study was conducted at the Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from September 2017 to February 2018, and comprised patients with suspected parathyroid disorders. A panel of biochemical tests were used for diagnosis of parathyroid disorders, which included parathyroid hormone levels, total calcium, ionized calcium, inorganic phosphorus, alkaline phosphatase, magnesium, total vitamin D and urinary calcium-to-creatinine ratio. SPSS 24 was used for data analysis. RESULTS: Of the 384 subjects, 248(65%) were male and 136(35%) were female. Overall mean age was 48±19years. Of the total, 302(786%) had parathyroid issues, with 244(81%) having secondary hyperparathyroidism. Mean serum total calcium, phosphorus, ionized calcium, magnesium and total vitamin D were 8.98±1.52 mg/dl, 4.0±1.30 mg/dl, 4.65±0.52 mg/dl, 2.11±0.27 mg/dl and 20.5±8.52 ngml respectively. Of the patients diagnosed with secondary hyperparathyroidism, 72.2% patients had chronic kidney disease and 20.2% had isolated vitamin D deficiency. CONCLUSIONS: Parathyroid disorders had significant impact on bone health. Moreover, secondary hyperparathyroidism was seen to be emerging as a major endocrine problem, especially in chronic kidney disease patients and vitamin D-deficient individuals.

Role of Vitamin D in Patients with Heart Failure with Reduced Ejection Fraction.

Heart failure (HF) with reduced ejection fraction (HFrEF) presents as the severest phenotype on the spectrum of HF. Although great progress has been made with respect to its treatment over the past 3 decades, morbidity and mortality remain high, posing a big burden on human health. Recent evidence suggests vitamin D has a critical role in maintaining heart health through activation of the vitamin D receptor expressed in cardiomyocytes, and vitamin D deficiency may be implicated in the pathophysiology of HFrEF through activation of the renin-angiotensin system, impaired calcium handling, exaggerated inflammation, secondary hyperparathyroidism, pro-fibrotic properties, and proatherogenic potential. Additionally, epidemiological data disclosed that vitamin D deficiency is highly prevalent in patients with HFrEF and is associated with poor clinical outcomes. However, randomized control trials of vitamin D supplementation in HF, especially in HFrEF, have shown inconsistent results. Thus, this article aims to review the epidemiology, pathophysiology, and prognostic value of vitamin D deficiency in HF, with a special focus on randomized control trials associated with vitamin D supplementation in patients with HFrEF.

Calcium and Vitamin D Supplementation. Myths and Realities with Regard to Cardiovascular Risk.

Vitamin D and calcium are considered crucial for the treatment of bone diseases. Both vitamin D and calcium contribute to bone homeostasis but also preserve muscle health by reducing the risk of falls and fractures. Low vitamin D concentrations result in secondary hyperparathyroidism and contribute to bone loss, although the development of secondary hyperparathyroidism varies, even in patients with severe vitamin D deficiency. Findings from observational studies have shown controversial results regarding the association between bone mineral density and vitamin D/calcium status, thus sparking a debate regarding optimum concentrations of 25-hydroxyvitamin D and calcium for the best possible skeletal health. Although most of the intervention studies reported a positive effect of supplementation with calcium and vitamin D on bone in patients with osteoporosis, this therapeutic approach has been a matter of debate regarding potential side effects on the cardiovascular (CV) system. Thus, the aim of this review is to consider the current evidence on the physiological role of vitamin D and calcium on bone and muscle health. Moreover, we provide an overview on observational and interventional studies that investigate the effect of vitamin D and calcium supplementation on bone health, also taking into account the possible CV side-effects. We also provide molecular insights on the effect of calcium plus vitamin D on the CV system.

Vitamin D Deficiency and Its Influence on Bone Metabolism and Density in a Brazilian Population of Healthy Men.

Vitamin D supplementation is universal for postmenopausal women, but not for elderly men, in whom osteoporosis is also commonly neglected. This study aimed to evaluate vitamin D deficiency and its association with secondary hyperparathyroidism, bone resorption, and bone density in Brazilian men. A total of 120 men, 20-93 years, were evaluated for serum calcium, phosphorus, creatinine, 25-hydroxyvitamin D (25(OH)D), parathyroid hormone, biochemical markers of bone resorption (carboxy-terminal telopeptide, carboxy-terminal peptide of type I collagen), and bone mineral density (dual-energy X-ray absorptiometry). Glomerular filtration rate (GFR) below 30 mL/min/1.73 m2, chronic diseases, and medications affecting bone were the exclusion criteria. No participant reported previous low-impact fractures. In the overall population, 25(OH)D levels were below 30 ng/mL in 46.7%, and below 20 ng/mL in 27.6%. Among the 93 patients 50 years and older, 28 had osteoporosis. In those 70 years and older, the prevalence of vitamin D deficiency (42.1%), secondary hyperparathyroidism (46.4%), high bone resorption (39.6%), decreased GFR (39.2%), and osteoporosis (41.4%) was significantly higher than in the younger subjects (p < 0.005 for all comparisons). Serum parathyroid hormone increased with aging and declining GFR, but was not significantly associated with 25(OH)D or bone mineral density. There was a clear contribution of vitamin D deficiency to increased bone resorption and osteoporosis. Binary logistic regression model considering age, 25(OH)D, and bone resorption identified age ≥70 years as the main determinant of osteoporosis. Our data demonstrate a high prevalence of vitamin D deficiency in a male population living in Rio de Janeiro, and emphasize its participation on the pathogenesis of age-related bone loss. (Vitamin D deficiency and osteoporosis are common in elderly Brazilian men.).

High Incidence of Secondary Hyperparathyroidism in Bariatric Patients: Comparing Different Procedures.

BACKGROUND: Bariatric surgery is an effective therapy for morbid obesity but may reduce calcium absorption and significantly decrease the bone mineral density. This study examined the prevalence of secondary hyperparathyroidism (SHPT) in obese subjects during follow-up after different bariatric surgeries. We investigated predictors of SHPT. METHODS: We enrolled 1470 obese subjects undergoing bariatric/metabolic surgery with at least 1-year follow-up, including 322 patients undergoing Roux-en-Y gastric bypass (RYGB), 695 undergoing single anastomosis (mini-) gastric bypass (SAGB), 93 undergoing laparoscopic adjustable gastric banding (LAGB), and 360 undergoing sleeve gastrectomy (SG). Five years of data were available for 215 patients. Patients were instructed to supplement their diet according to the guideline. Calcium, parathyroid hormone (PTH), and vitamin D levels were measured before surgery and at 1 and 5 years after surgery. SHPT was defined as PTH > 69 pg/mL. RESULTS: The overall prevalence of SHPT was high, 21.0% before surgery and was not different between patients with different bariatric procedures. Pre-operative PTH correlated with age, BMI, and vitamin D levels. Multi-variate analysis confirmed that vitamin D level was the only independent predictor of SHPT before surgery. The prevalence of SHPT increased to 35.4% at 1 year after surgery and 63.3% at 5 years after surgery. SAGB had the highest prevalence of SHPT (50.6%) followed by RYGB (33.2%), LAGB (25.8%), and SG (17.8%) at 1 year after surgery. At 5 years after surgery, SAGB still had the highest prevalence of SHPT (73.6%), followed by RYGB (56.6%), LAGB (38.5%), and SG (41.7%). Serum PTH at 1 year after surgery correlated with decreased BMI and weight loss. Multi-variate analysis confirmed that age, sex, calcium level, and bypass procedure were independent predictor of SHPT after surgery. CONCLUSIONS: The prevalence of SHPT is high in morbidly obese patients before bariatric surgery which is related to vitamin D deficiency. The prevalence of SHPT increased continually along with the time after bariatric surgery, especially in patients receiving SAGB, followed by RYGB. The supplementation of vitamin D and calcium have to be higher in bypass procedure, especially in malabsorptive procedure.

Elderly patients with chronic kidney disease have higher risk of hyperparathyroidism.

PURPOSE: As the world's population ages, the incidence of chronic kidney disease (CKD) is growing. There is ongoing debate regarding whether high levels of parathyroid hormone (PTH) would be more common in elderly than young patients, and which factors are driven the risk of secondary hyperparathyroidism (SHPT), independent of renal function. METHODS: Elderly patients (age ≥ 65 years, N = 518) were compared to a 1:1 sex- and estimated glomerular filtration rate (eGFR)-matched sample of young patients (age < 65 years), in a cross-sectional analysis. Demographic, biochemical and drug prescription data were collected from electronic charts. The main outcome measure was the prevalence of SHPT, defined as PTH > 65 pg/mL. RESULTS: Elderly patients presented higher serum calcium and PTH levels and lower serum phosphate, and were taking more diuretics than young patients. SHPT was more frequent among elderly patients (49.4 vs. 38.6%, p = 0.005), and it was associated with lower eGFR, low levels of 25(OH) vitamin D and with furosemide therapy, while thiazide use was a protector factor. Elderly patients with 25(OH) vitamin D > 40 ng/mL were protected against SHPT. The Ca/PTH ratio was lower in elderly than in young patients [0.15 (0.10, 0.20) vs. 0.16 (0.11, 0.23), respectively, p = 0.003]. CONCLUSION: CKD elderly patients have higher risk of SHPT than young, which cannot be explained solely by renal function. Besides low levels of vitamin D, furosemide therapy and a distinct relationship between calcium and PTH are possible factors contributing to SHPT. Whether this is a result of renal resistance to PTH or an altered set point to calcium deserves further investigation.

Long-term hypovitaminosis D and secondary hyperparathyroidism outcomes of the Roux-en-Y gastric bypass: a systematic review.

INTRODUCTION: Pre-operative Vitamin D deficiency is markedly prevalent in prospective bariatric surgery patients. While bariatric surgery leads to significant weight loss, it can exacerbate or prolong Vitamin D deficiency. We systematically reviewed the literature to assess whether secondary hyperparathyroidism is maintained in the medium to long term in patients following the Roux-en-Y gastric bypass. METHODS: A comprehensive literature search was conducted through Medline, Embase, Scopus, Web of Science, Dare, Cochrane library and HTA database. The search terms used were bariatric surgery, gastric bypass and hyperparathyroidism. RESULTS: Fourteen studies were included (n = 2688 subjects). Parathyroid hormone levels rose gradually from a mean pre-operative level of 5.69 ± 1.2 pmol/L to 6.36 ± 0.77 pmol/L, 7.59 ± 0.73 pmol/L and 8.29 ± 1.41 pmol/L at 2 years, between 2 and 5 years, and beyond 5 years, respectively. Vitamin D levels slowly fell to a mean of 20.50 ± 4.37 ng/mL and 20.76 ± 3.80 ng/mL between follow-up intervals 2-5 years and beyond 5, respectively. CONCLUSION: It appears that hyperparathyroidism persists at 5-year follow-up after gastric bypass, despite most patients being supplemented with calcium and Vitamin D.

Rates of secondary hyperparathyroidism after bypass operation for super-morbid obesity: An overlooked phenomenon.

BACKGROUND: With over 110,000 bariatric operations performed in the United States annually, it is important to understand the biochemical abnormalities causing endocrine dysfunction associated with these procedures. Here we compare 2 malabsorptive procedures, duodenal switch and Roux-en-Y gastric bypass, to determine the role malabsorption plays in secondary hyperparathyroidism in this population. METHODS: Data from all super-obese patients undergoing duodenal switch or Roux-en-Y gastric bypass between August 2002 and October 2005 were prospectively collected. Postoperatively, all patients received 1,200 mg of calcium citrate and 1,000 IU vitamin D3 per American Society for Metabolic and Bariatric Surgery guidelines. Beginning in 2007, duodenal switch patients were instructed to add daily vitamin D3 10,000 IU. Statistical analyses included Student t test, multivariate, and univariate logistic regression. RESULTS: Of 283 patients with a body mass index ≥50, 170 (60.1%) underwent duodenal switch, while 113 (39.9%) underwent Roux-en-Y gastric bypass. Of 132 (46.6%) patients with secondary hyperparathyroidism, 101 (59.4%) had undergone duodenal switch and 31 (27.4%) had undergone Roux-en-Y gastric bypass. Symptoms were more common in the duodenal switch group (33 patients [19.4%]) than Roux-en-Y gastric bypass (11 patients [9.7%]). Multivariate logistic regression demonstrated that the extent of bypass and duration of follow-up were the only 2 independent predictive risk factors for developing secondary hyperparathyroidism. Although vitamin D levels improved with increased vitamin D3 supplementation in 2007, rates of secondary hyperparathyroidism increased. CONCLUSION: Despite routine postoperative calcium and vitamin D3 supplementation, secondary hyperparathyroidism is common after Roux-en-Y gastric bypass and duodenal switch. The degree of iatrogenic malabsorption correlates with the incidence of secondary hyperparathyroidism. These rates suggest current supplementation guidelines are not sufficient in preventing secondary hyperparathyroidism. Further work is needed to better define the sequelae of long-term hyperparathyroidism.

Hypertension is a characteristic complication of X-linked hypophosphatemia.

X-linked hypophosphatemia (XLH) is a group of rare disorders caused by defective proximal tubular reabsorption of phosphate. Mutations in the PHEX gene are responsible for the majority of cases. There are very few reports of long-term complications of XLH other than skeletal and dental diseases. The aim of this study was to identify the phenotypic presentation of XLH during adulthood including complications other than skeletal and dental diseases. The clinical and biochemical phenotype of 22 adult patients with a PHEX gene mutation were examined retrospectively from their medical records. 6 patients had hypertension. The average age of hypertension onset was 29.0 years. Secondary hyperparathyroidism preceded the development of hypertension in 5 patients. 1 patient developed tertiary hyperparathyroidism. 15 patients had nephrocalcinosis. 2 patients had chronic renal dysfunction. Patients with hypertension had a significantly lower eGFR (p=0.010) compared to patients without hypertension. No significant difference was found in any other parameters. To examine the genotype-phenotype correlation, 10 adult males were chosen for analysis. No significant genotype-phenotype correlation analysis was revealed in any of the complications. However, there was a possibility that the age at nephrocalcinosis onset was younger in the non-missense mutation group than in the missense mutation group (p=0.063). This study corroborated the view that early-onset hypertension could be one of the characteristic complications seen in XLH patients. Considering the limited number of our patients, further study is necessary to address a potential cause of hypertension. XLH patients require careful lifelong treatment.

Differences in the prevalence of vitamin D deficiency and hip fractures in nursing home residents and independently living elderly

ABSTRACT Objective To compare the prevalence of vitamin D deficiency and fracture history in nursing home residents and community-dwelling elderly subjects and to explore the association of vitamin D levels with various characteristics. Materials and methods Sixty-six nursing home residents and 139 community-dwelling elderly subjects participated. Marital status, medical history, medication including vitamin D supplements, smoking, past fractures were assessed. Weight and height were measured and body mass index calculated. Serum 25-hydroxyvitamin D (25-OHD), PTH, Ca, phosphate, creatinine and eGFR were determined. Results In the nursing home residents 25-OHD was lower (17.8 nmol/l, [9.4-28.6] vs. 36.7 nmol/l, [26.9-50], p < 0.001), PTH was higher (5.6 pmol/l, [3.9-8.9] vs. 4.7 pmol/l [3.6-5.8], P = 0.003) and 25-OHD deficiency was more prevalent (65.2% [53.7-76.7] vs. 22.3% [15.4-29.2], p < 0.001) as was elevated PTH (23% [12.8-33] vs. 5.8% [2-10], p = 0.001). 25-OHD correlated negatively with PTH (institutionalized r = -0.28, p = 0.025 and community-dwelling r = -0.36, p < 0.001). Hip fractures were reported by 8% of the residents and 2% of the independent elderly. The only predictor for hip fracture was elevated PTH (OR = 7.6 (1.5-36.9), p = 0.013). Conclusion The prevalence of vitamin D deficiency and secondary hyperparathyroidism was high in the institutionalized subjects. Hip fracture risk was associated with elevated PTH and not directly with vitamin D levels or the residency status.

Differences in the prevalence of vitamin D deficiency and hip fractures in nursing home residents and independently living elderly.

OBJECTIVE: To compare the prevalence of vitamin D deficiency and fracture history in nursing home residents and community-dwelling elderly subjects and to explore the association of vitamin D levels with various characteristics. MATERIALS AND METHODS: Sixty-six nursing home residents and 139 community-dwelling elderly subjects participated. Marital status, medical history, medication including vitamin D supplements, smoking, past fractures were assessed. Weight and height were measured and body mass index calculated. Serum 25-hydroxyvitamin D (25-OHD), PTH, Ca, phosphate, creatinine and eGFR were determined. RESULTS: In the nursing home residents 25-OHD was lower (17.8 nmol/l, [9.4-28.6] vs. 36.7 nmol/l, [26.9-50], p < 0.001), PTH was higher (5.6 pmol/l, [3.9-8.9] vs. 4.7 pmol/l [3.6-5.8], P = 0.003) and 25-OHD deficiency was more prevalent (65.2% [53.7-76.7] vs. 22.3% [15.4-29.2], p < 0.001) as was elevated PTH (23% [12.8-33] vs. 5.8% [2-10], p = 0.001). 25-OHD correlated negatively with PTH (institutionalized r = -0.28, p = 0.025 and community-dwelling r = -0.36, p < 0.001). Hip fractures were reported by 8% of the residents and 2% of the independent elderly. The only predictor for hip fracture was elevated PTH (OR = 7.6 (1.5-36.9), p = 0.013). CONCLUSION: The prevalence of vitamin D deficiency and secondary hyperparathyroidism was high in the institutionalized subjects. Hip fracture risk was associated with elevated PTH and not directly with vitamin D levels or the residency status.

Low serum 25-hydroxyvitamin D levels and secondary hyperparathyroidism in Fontan patients.

BACKGROUND: Limited data exist on the vitamin D status in Fontan patients. We determined the prevalence and potential risk factors of vitamin D deficiency in this patient subset. Methods and results Data were collected from 27 Fontan patients (55.6% male, mean age 8.1±5.3 years). Protein-losing enteropathy was diagnosed in six patients (22.2%). Vitamin D deficiency was defined as a serum 25-hydroxyvitamin D level of <20 ng/ml. The neutrophil-to-lymphocyte ratio, a marker of systemic inflammation, was calculated. Associations between laboratory measurements and patient characteristics were explored. Mean serum 25-hydroxyvitamin D level was 14.1±10.4 ng/ml. Vitamin D deficiency was found in 19/27 patients (70.3%). Only skin type was associated with vitamin D deficiency (p=0.04). Hyperparathyroidism was present in 5/21 (23.8%) patients, and was more prevalent in patients with protein-losing enteropathy (p<0.001). Parathyroid hormone levels correlated with parameters of systemic inflammation (neutrophil-to-lymphocyte ratio: r=0.484, p=0.026; relative lymphocyte count: r=-0.635, p=0.002). Vitamin D supplementation significantly increased serum 25-hydroxyvitamin D levels (p<0.0001), and was accompanied by a reduction in parathyroid hormone concentrations (p=0.032). CONCLUSIONS: A high prevalence of vitamin D deficiency was found among Fontan patients, independent of age, time after Fontan procedure, ventricular morphology, and presence of protein-losing enteropathy. A potentially important link between parathyroid hormone levels and systemic inflammation is suggested.

Prevalence and correlates of 25-hydroxyvitamin D deficiency in the Chronic Kidney Disease in Children (CKiD) cohort.

BACKGROUND: Vitamin D plays an important role in the mineral and bone disorder seen in chronic kidney disease (CKD). Deficiency of 25-hydroxyvitamin D (25OHD) is highly prevalent in the adult CKD population. METHODS: The prevalence and determinants of 25OHD deficiency (defined as a level <20 ng/ml) were examined longitudinally in 506 children in the CKiD cohort. Predictors of secondary hyperparathyroidism and the determinants of 1,25-dihydroxyvitamin D (1,25(OH)2D) levels were also evaluated. RESULTS: Deficiency of 25OHD was observed in 28 % of the cohort at enrollment. Significant predictors of 25OHD deficiency were older age, non-white race, higher body mass index, assessment during winter, less often than daily milk intake, non-use of nutritional vitamin D supplement and proteinuria. Lower values of glomerular filtration rate (GFR), serum 25OHD, calcium and higher levels of FGF23 were significant determinants of secondary hyperparathyroidism. Lower GFR, low serum 25OHD, nephrotic-range proteinuria, and high FGF23 levels were significant determinants of serum 1,25(OH)2 D levels. CONCLUSIONS: Deficiency of 25OHD is prevalent in children with CKD and is associated with potentially modifiable risk factors such as milk intake, nutritional vitamin D supplement use, and proteinuria. 25OHD deficiency is a risk factor for secondary hyperparathyroidism and decreased serum 1,25(OH)2D in children with CKD.

Prevalence of secondary hyperparathyroidism in patients with stage 3 and 4 chronic kidney disease seen in internal medicine.

OBJECTIVE: Despite the high prevalence of chronic kidney disease in the elderly population, few data are available on the frequency of secondary hyperparathyroidism in the Spanish population affected by this problem. We undertook a study on this issue in patients attending the internal medicine departments in our area. DESIGN AND METHODS: An observational, cross-sectional survey performed at internal medicine departments on 415 patients with stage 3 and 4 chronic kidney disease. Clinical history and risk factors were collected using a standardized protocol. Serum creatinine, phosphate, calcium, intact parathormone (PTH) and 25-hydroxy-cholecalciferol (25-OH-vitD) levels were measured in all patients. RESULTS: Among stage 3 patients, 62.9% had PTH levels ≥70pg/mL and 32.7% levels ≥110pg/mL. Median PTH level in stage 4 patients was 120pg/mL (p <0.001), and 77.9% of these patients had PTH ≥70pg/mL (p <0.001) and 54.1% ≥110pg/mL (p=0.015). Adequate 25-hydroxy-cholecalciferol levels were found in only 7.2% of stage 3 patients and 4.1% of stage 4 patients. Only 7.2% of stage 3 patients had hyperphosphatemia, as compared to 25.4% of stage 4 patients (p <0.001). CONCLUSIONS: Hyperparathyroidism is a common complication of stage 3 and 4 chronic kidney disease which is not associated to detectable changes in serum calcium and phosphate levels. It is therefore advisable to measure PTH levels in all patients with decreased glomerular filtration rate.

Mineral metabolism in European children living with a renal transplant: a European society for paediatric nephrology/european renal association-European dialysis and transplant association registry study.

BACKGROUND AND OBJECTIVES: Data on mineral metabolism in pediatric renal transplant recipients largely arise from small single-center studies. In adult patients, abnormal mineral levels are related to a higher risk of graft failure. This study used data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry to study the prevalence and potential determinants of mineral abnormalities, as well as the predictive value of a disturbed mineral level on graft survival in a large cohort of European pediatric renal transplant recipients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study included 1237 children (0-17 years) from 10 European countries, who had serum calcium, phosphorus, and parathyroid hormone measurements from 2000 onward. Abnormalities of mineral metabolism were defined according to European guidelines on prevention and treatment of renal osteodystrophy in children on chronic renal failure. RESULTS: Abnormal serum phosphorus levels were observed in 25% (14% hypophosphatemia and 11% hyperphosphatemia), altered serum calcium in 30% (19% hypocalcemia, 11% hypercalcemia), and hyperparathyroidism in 41% of the patients. A longer time since transplantation was associated with a lower risk of having mineral levels above target range. Serum phosphorus levels were inversely associated with eGFR, and levels above the recommended targets were associated with a higher risk of graft failure independently of eGFR. CONCLUSIONS: Abnormalities in mineral metabolism are common after pediatric renal transplantation in Europe and are associated with graft dysfunction.

Effect of a monthly dose of calcidiol in improving vitamin D deficiency and secondary hyperparathyroidism in HIV-infected patients.

There are no data about the optimal supplementation therapy in HIV-infected patients with vitamin D (25OHD) deficiency. The aim of this study was to assess the effect of an oral monthly dose of 16,000 IU calcidiol. We performed a longitudinal cohort study of 365 HIV-infected patients (24 % females) was with sequential determinations of 25OHD, serum parathyroid hormone (PTH), calcium, and alkaline phosphatase. The efficacy and safety of supplementation in 123 patients were compared against dietary and sun exposure advice. Overall, mean baseline 25OHD levels were 19.1 ng/ml (IQR 12-23.6), 63 % of patients had 25OHD deficiency and 27 % secondary hyperparathyroidism. After a median time of 9.3 months (95.61 patients-year on-treatment), 25OHD levels increased in comparison with non-supplemented patients (+16.4 vs. +3.2 ng/ml; p < 0.01), decreasing the rate of 25OHD deficiency (from 84 to 24 %), and decreasing serum PTH (-4.9 pg/ml) and the rate of secondary hyperparathyroidism (from 43 to 31 %; p < 0.001). This improvement was observed irrespective of HIV/HCV coinfection or the use of efavirenz. In a regression analysis, adjusting by seasonality, a lower baseline 25OHD was associated with persistence of deficiency (relative risk, RR 1.07; 95 % CI 1.03-1.1; p < 0.001), whereas calcidiol supplementation was the only factor associated with significant improvement (RR 0.38; 95 % CI 0.12-0.46; p < 0.001). This monthly dose showed no clinical toxicity, and no patient had 25OHD levels above 100 ng/ml, nor hypercalcemia. The use of monthly calcidiol is safe, easy to take, and largely effective to improve vitamin D deficiency and secondary hyperparathyroidism in HIV-infected patients.