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Chronic kidney disease is associated with
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low BMD at the hip but not at the spine
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from Jules: up to 30% of PLWH over 65 have been reported to have chronic kidney disease, as one ages kidney function declines in the general population but as with other comorbidities the rate of kidney disease in older HIV+ over 60 is 2-3 times higher compared to the general population. In the general population once a bone fracture occurs in a person over 65 mortality/death risk increases a lot, fracture rate as well are double among older HIV+ compared to the same age group in the general population.
In summary, we have demonstrated that osteopenia and osteoporosis were highly prevalent in patients with CKD and seem to be more likely to occur as the renal function deteriorates, with aging, and in patients with PTH higher than 65 pg/ml. Indeed, hyperparathyroidism was associated with high risk of reduced BMD, particularly at the hip, opening a new avenue for research. Whether this finding explains the high prevalence of hip over spine fracture in patients with CKD deserves further studies. Knowing that reduced BMD in patients with CKD, as measured by DXA, can predict the risk of fracture, and in face of accumulated evidence to date, complacency with a contemplative care practice regarding osteoporosis needs to change. There is a need for a placebo-controlled prospective study to assess the effect of treatment of these conditions on mineral density, quality of life, fracture risk, and mortality.
As CKD progressed, the percentage of patients with normal BMD decreased, whereas the percentage of osteopenia and osteoporosis increased, With eGFR > 90 ml/min as reference, the odds ratios for osteoporosis/osteopenia at the hip were 1.51 (95% CI 1.01–2.24) and 1.91 (95% CI 1.13–3.20) for patients with eGFR 30–60 and 15–30 ml/min/1.73 m2, respectively.....Taken together, our data suggest that hip fracture might be associated with hyperparathyroidism and low BMD in patients with CKD, whereas spine fractures are similar to those observed in the general population and cannot be predicted by low BMD......we observed low hip BMD mostly in patients with eGFR < 60 ml/min/1.73 m2. This result can be explained by a greater impairment of cortical than trabecular bone in patients with CKD, a finding already demonstrated by peripheral quantitative computed tomography (HRpQCT) [29].....We found that hyperparathyroidism was associated with low BMD in patients with CKD....It should be noted that for the same age, the risk of having osteoporosis/osteopenia is much higher in the presence of hyperparathyroidism.
Known risk factors for fractures in the general population can be exacerbated by CKD, such as hormonal deficiency [4], falls [5], and sarcopenia [6]. Fractures were reported to be greater than 2- to 100-fold more common in CKD than in age-matched individuals without CKD [7, 8, 9]. In patients with predialysis CKD, a history of osteoporosis was reported to be associated with a greater than 2-fold odds of hip fracture compared with the general population [8]. Most importantly, mortality rates after fracture were 3-fold greater in patients with CKD [10].
The present study included a large sample size of individuals with stages 1–5 CKD providing several insights about the features of BMD in this population. First, we confirmed that patients with low BMD were more likely to be women and older, findings similar to those in the general population. In addition, we demonstrated the association between low BMD and impaired renal function, since osteopenia/osteoporosis seems to be more prevalent as CKD progresses. Second, in patients with eGFR < 60 ml/min/1.73 m2, hip is the elected bone site for osteopenia/osteoporosis, which is closely related to the presence of hyperparathyroidism.
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Chronic kidney disease is associated with low BMD at the hip but not at the spine
May 2019 Osteoporosis International K. S. Bezerra de Carvalho1 & R.F.V. Vasco1 & M.R. Custodio1 & V. Jorgetti1,2 & R.M.A. Moysés1,3 & R.M. Elias1,3
Abstract
Summary
Although chronic kidney disease is associated with other bone disorders, osteoporosis can be found in this context, and it is defined based on bone mineral density (BMD), measured by dual-energy X-ray absorptiometry. As CKD progresses, the percentage of normal BMD decreases, whereas that of osteopenia/osteoporosis increases, mostly due to hip involvement, particularly in patients with reduced renal function.
Introduction
Osteoporosis is a highly prevalent disease in patients with chronic kidney disease (CKD). We investigated the features of bone mineral density (BMD) in patients with assorted kidney diseases and hypothesized that low BMD, as measured by dual-energy X-ray absorptiometry (DXA), would be more prevalent as kidney function decreased and would correlate with biomarkers of mineral and bone disease.
Methods
DXA obtained from January 1, 2008, to December 31, 2017, clinical, demographic, and biochemical data at the time of image acquisition were recorded. Data from 1172 patients were included in this study (81.3% women, 79.9% white, and 8.1% diabetic).
Results
Osteopenia and osteoporosis in at least one site (total hip or spine) were found in 32.7% and 20.0% of patients, respectively. As CKD progressed, the percentage of patients with normal BMD decreased, whereas the percentage of osteopenia and osteoporosis increased, which was mostly due to the total hip involvement, particularly in patients with estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2. Older age and hyperparathyroidism were independent risk factors for osteopenia/osteoporosis at the total hip; female gender, older age, and higher iCa were independently associated with the risk of osteopenia/osteoporosis at the spine. With eGFR > 90 ml/min as reference, the odds ratios for osteoporosis/osteopenia at the hip were 1.51 (95% CI 1.01–2.24) and 1.91 (95% CI 1.13–3.20) for patients with eGFR 30–60 and 15–30 ml/min/1.73 m2, respectively. No CKD stage was significantly associated with the risk of osteoporosis/osteopenia at the spine.
Conclusion
Our results highlighted that low BMD in patients with CKD is associated with age and hyperparathyroidism, and affects predominantly the hip.
Introduction
Osteoporosis is a disorder of low bone mass and impaired bone strength, causing an increased risk for fracture in the general population [1]. Chronic kidney disease (CKD) is a highly prevalent disease characterized by gradual loss of kidney function. According to Kidney Disease Improving Global Outcomes (KDIGO), it is defined as kidney damage (albuminuria) or glomerular filtration rate (GFR) < 60 ml/min/1.73 m2 for 3 months or more, irrespective to cause [2]. Fractures are very common in patients with CKD, and their occurrence cannot be entirely explained by the aging population, since children with CKD have 3-fold increased fracture risk [3]. Known risk factors for fractures in the general population can be exacerbated by CKD, such as hormonal deficiency [4], falls [5], and sarcopenia [6]. Fractures were reported to be greater than 2- to 100-fold more common in CKD than in age-matched individuals without CKD [7, 8, 9]. In patients with predialysis CKD, a history of osteoporosis was reported to be associated with a greater than 2-fold odds of hip fracture compared with the general population [8]. Most importantly, mortality rates after fracture were 3-fold greater in patients with CKD [10].
Data from the National Health and Nutrition Examination Survey (NHANES) suggest that CKD and osteoporosis are highly co-prevalent [8, 11], such that Moe and cols suggest the term CKD-induced osteoporosis [12], in the same way we use the expression steroid-induced osteoporosis. Among NHANES III participants, osteoporosis was twice as common in those with an estimated GFR (eGFR) < 60 ml/min when compared to those with an eGFR ≥ 60 ml/min [8].
The dual-energy X-ray absorptiometry (DXA) is the gold standard method to measure bone mass and has been demonstrated to predict fracture risk in the general population. In contrast, the role of DXA in fracture risk assessment in CKD has been controversial. The 2009 KDIGO guidelines was recommended against routine bone mineral density (BMD) testing. However, more recent prospective trials in patients with predialysis CKD [13, 14] and in patients with end-stage renal disease on hemodialysis [15] indicate that low areal BMD measured by DXA at the forearm (one-third and ultra-distal radius), hip (total and femoral neck), and spine can, indeed, predict a future fracture. These studies support the clinical use of DXA as a fracture risk-screening tool in CKD, which was recognized by the update of KDIGO in 2016 [16], indicating that the same T-score cutoffs for osteopenia and osteoporosis can be used for CKD patients as for the general population.
The prevalence of osteopenia/osteoporosis is not well established among patients with CKD and, when available, is mostly obtained from patients not yet on dialysis [13]. Therefore, we ought to investigate the prevalence and pattern of BMD, as measured by DXA, in a cross section of patients with 1–5 CKD stages, in a decade of observation. We hypothesized that first, low BMD will be more prevalent as kidney function decreases and second, biomarkers of CKD-MBD will be associated with altered BMD.
The analysis according to renal function (Table 2) showed that patients with eGFR > 90 ml/min/1.73 m2 were younger; hyperparathyroidism (PTH > 65 pg/ml) was more frequent in late stages of CKD. As CKD progresses, the percentage of patients with normal BMD decreases, whereas the percentage of osteopenia and osteoporosis increases (Table 2). However, the difference between initial and late stages of CKD was more prominent at the total hip. Indeed, hip was more affected than spine, as assessed by DXA, in patients with and eGFR < 60 ml/min (Supplementary Table 1). Accordingly, osteopenia and/or osteoporosis was found only at the hip in 1.6%, only at the lumbar spine in 26.6%, in both sites in 9.5% and in none of sites in 62.3% of cases among patients with eGFR ≥ 60 ml/min/1.73 m2, whether in patients with eGFR < 60 ml/min/1.73 m2 was found only at the hip in 15.9%, only at the lumbar spine in 25.5%, in both sites in 15.6% and in none of the sites in 43.0%, difference that was statistically significant (p < 0.0001). Mean and 95% confidence intervals of T-scores at the total hip and spine, according to eGFR category, are illustrated in Fig. 1. T-scores at the total hip correlated with age (r = − 0.324, p = 0.007), iCa (r = − 0.332, p = 0.009), and 25 vitamin D (r = 0.310, p = 0.027); T-scores at the spine correlated with age (r = − 0.314, p = 0.008), iCa (r = − 0.306, p = 0.016), and phosphate (r = 0.278, p = 0.026).
About 132 patients had repeated DXA during the study period, 80 with initial eGFR ≥ 60 ml/min/1.73 m2 and 52 already with initial eGFR < 60 ml/min/1.73 m2. In this latter subgroup of patients with CKD, T-scores worsened at spine in 17 (32.7%) and at hip in 16 (30.8%) patients, with 6 (11.5%) patients getting worse in both sites.
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