Chronic kidney disease (CKD) is one of the most important public health issues worldwide, with around 10–13% of the adult population suffering from the condition; it has significant morbidity, mortality, and healthcare cost implications. Loss of kidney function leads to several physiological abnormalities, such as disturbances in calcium, phosphate, vitamin D, and parathyroid hormone (PTH) metabolism, which are complex together and are known as chronic kidney disease–mineral and bone disorder (CKD-MBD). The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines define CKD-MBD as a systemic disease consisting of abnormalities of mineral metabolism, disturbances of bone metabolism and mineralization, and extra-skeletal calcification (especially vascular and soft tissue calcification) [1,2]. Patients with end-stage kidney disease (ESKD) who are on maintenance hemodialysis are especially susceptible to CKD-MBD, due to a high likelihood of severely impaired phosphate clearance, low renal production of 1,25(OH)2D, chronic hypocalcemia, and ongoing parathyroid stimulation. These abnormalities lead to secondary hyperparathyroidism, high-turnover bone disease, osteomalacia, adynamic bone disease, and progressive vascular calcification. Therefore, CKD-MBD significantly contributes to the risk of pathological fracture, bone pain, cardiovascular events, hospitalization, and death. Cardiovascular disease is the major cause of death in maintenance hemodialysis patients, and mineral metabolism disorders are important factors in its pathogenesis [3,4]. Hyperphosphatemia is one of the earliest and most clinically important biochemical abnormalities in advanced CKD. Persistent disturbances in calcium-phosphate homeostasis occur due to the effect of elevated serum phosphate on increasing the secretion of fibroblast growth factor-23 (FGF-23) and parathyroid hormone (PTH) and decreasing the production of calcitriol. At the same time, low vitamin D levels decrease calcium absorption from the intestine and worsen hypocalcemia and secondary hyperparathyroidism. If PTH is persistently high, it continues to cause bone loss, increasing bone turnover and causing bone fragility and decreased mineralization. High levels of calcium phosphate also lead to vascular smooth muscle calcification, causing arterial stiffness, left ventricular hypertrophy, ischemic heart disease, and cardiovascular mortality [5,6]. Maintenance HD patients have been reported to have CKD-MBD (60-90%) with significant regional variation in rates of this condition due to differences in dietary habits, dialysis adequacy, access to phosphate binders and vitamin D therapy, and routine biochemical monitoring. Low- and middle-income countries (LMICs) are likely to have more complex biochemical abnormalities at presentation because of delayed diagnosis, cost, and a lack of specialist nephrology services. Diabetes mellitus, hypertension, obesity, and aging are the precipitating factors in Pakistan, where the prevalence of chronic kidney disease is also growing. Despite this increasing burden, there is a lack of published local information on the prevalence and epidemiology of CKD-MBD [7,8]. Prompt detection and treatment of mineral metabolism disturbances is critical because dietary phosphate restriction, phosphate binders, vitamin D analogs, calcimimetics, and adequate dialysis can help to decrease complications and enhance patient outcomes. KDIGO recommends that patients on maintenance HD be monitored with regular tests of serum calcium, phosphate, intact parathyroid hormone (iPTH), and alkaline phosphatase levels, and that vitamin D be monitored as well [9]. So, it is important to be familiar with local epidemiology of CKD-MBD to help inform evidence-based management and help prevent disease progression and cardiovascular complications.

Study Objectives

To assess the prevalence of chronic kidney disease–mineral and bone disorder in maintenance hemodialysis patients and its association with demographics, dialysis duration, and biochemical parameters.

Study Design & Setting

A cross-sectional study was conducted in the Department of Nephrology, Institute of Kidney Diseases, Hayatabad, Peshawar, Pakistan, from January 2025 to June 2025.

Study Population

Adult patients with end-stage kidney disease receiving maintenance hemodialysis at the nephrology unit were screened for eligibility. Eligible patients attending the maintenance hemodialysis unit during the study period were recruited using consecutive non-probability sampling after obtaining written informed consent until the required sample size was achieved.

Participants

All eligible patients attending the maintenance hemodialysis unit during the study period were screened consecutively for eligibility. Patients fulfilling the inclusion criteria and providing informed consent were enrolled until the required sample size was achieved.

Sample Size Calculation

The sample size was calculated using the WHO Sample Size Calculator based on the single population proportion formula (n = Z²P(1−P)/d²), assuming a prevalence of 50%, 95% confidence level, and 10% margin of error. The minimum required sample size was 96; therefore, 100 participants were enrolled.

Inclusion Criteria

• Adults aged ≥18 years.
• Diagnosed with end-stage kidney disease.
• Receiving maintenance hemodialysis for at least three months.
• Undergoing hemodialysis two or three times weekly.
• Provided written informed consent.

Exclusion Criteria

• Acute kidney injury.
• Previous parathyroidectomy.
• Active malignancy.
•  
• Inherited metabolic bone disease.
• Incomplete biochemical investigations.
• Refusal to participate.

Data Collection Procedure

After obtaining written informed consent, demographic and clinical information, including age, gender, duration of hemodialysis, body mass index, diabetes mellitus, and hypertension, was recorded using a structured data collection form. Venous blood samples were collected immediately before a scheduled hemodialysis session under aseptic conditions. Serum calcium, phosphate, alkaline phosphatase, intact parathyroid hormone, and 25-hydroxy vitamin D levels were analyzed using calibrated automated analyzers in the hospital laboratory following standard operating procedures and internal quality control measures. The principal investigator reviewed all laboratory results and clinical data to ensure completeness and accuracy before statistical analysis.

Diagnostic and Management Strategy

CKD-MBD was diagnosed according to the KDIGO 2017 Clinical Practice Guideline based on abnormalities in serum calcium, phosphate, intact parathyroid hormone, alkaline phosphatase, and 25-hydroxy vitamin D levels. Patients received routine clinical management according to institutional nephrology protocols; however, treatment outcomes were not evaluated because of the cross-sectional study design.

Statistical Analysis

Data were entered into SPSS version 27.0 after verification for completeness and accuracy. Normality of continuous variables was assessed using the Shapiro–Wilk test. Normally distributed variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. An independent-samples t-test was used to compare continuous variables, whereas the Chi-square test was applied for categorical variables. A two-tailed p-value <0.05 was considered statistically significant.

Study Design & Setting

A cross-sectional study was conducted in the Department of Nephrology, Institute of Kidney Diseases, Hayatabad, Peshawar, Pakistan, from January 2025 to June 2025.

Study Population

Adult patients with end-stage kidney disease receiving maintenance hemodialysis at the nephrology unit were screened for eligibility. Eligible patients attending the maintenance hemodialysis unit during the study period were recruited using consecutive non-probability sampling after obtaining written informed consent until the required sample size was achieved.

Participants

All eligible patients attending the maintenance hemodialysis unit during the study period were screened consecutively for eligibility. Patients fulfilling the inclusion criteria and providing informed consent were enrolled until the required sample size was achieved.

Sample Size Calculation

The sample size was calculated using the WHO Sample Size Calculator based on the single population proportion formula (n = Z²P(1−P)/d²), assuming a prevalence of 50%, 95% confidence level, and 10% margin of error. The minimum required sample size was 96; therefore, 100 participants were enrolled.

Inclusion Criteria

• Adults aged ≥18 years.
• Diagnosed with end-stage kidney disease.
• Receiving maintenance hemodialysis for at least three months.
• Undergoing hemodialysis two or three times weekly.
• Provided written informed consent.

Exclusion Criteria

• Acute kidney injury.
• Previous parathyroidectomy.
• Active malignancy.
•  
• Inherited metabolic bone disease.
• Incomplete biochemical investigations.
• Refusal to participate.

Data Collection Procedure

After obtaining written informed consent, demographic and clinical information, including age, gender, duration of hemodialysis, body mass index, diabetes mellitus, and hypertension, was recorded using a structured data collection form. Venous blood samples were collected immediately before a scheduled hemodialysis session under aseptic conditions. Serum calcium, phosphate, alkaline phosphatase, intact parathyroid hormone, and 25-hydroxy vitamin D levels were analyzed using calibrated automated analyzers in the hospital laboratory following standard operating procedures and internal quality control measures. The principal investigator reviewed all laboratory results and clinical data to ensure completeness and accuracy before statistical analysis.

Diagnostic and Management Strategy

CKD-MBD was diagnosed according to the KDIGO 2017 Clinical Practice Guideline based on abnormalities in serum calcium, phosphate, intact parathyroid hormone, alkaline phosphatase, and 25-hydroxy vitamin D levels. Patients received routine clinical management according to institutional nephrology protocols; however, treatment outcomes were not evaluated because of the cross-sectional study design.

Statistical Analysis

Data were entered into SPSS version 27.0 after verification for completeness and accuracy. Normality of continuous variables was assessed using the Shapiro–Wilk test. Normally distributed variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. An independent-samples t-test was used to compare continuous variables, whereas the Chi-square test was applied for categorical variables. A two-tailed p-value <0.05 was considered statistically significant.

A total of 100 patients undergoing maintenance hemodialysis were included in the study. The mean age was 52.8 ± 13.4 years (range: 21–79 years). There were 62 (62%) males and 38 (38%) females, giving a male-to-female ratio of 1.6:1. The mean duration of maintenance hemodialysis was 3.6 ± 1.8 years, while the mean body mass index was 25.4 ± 4.2 kg/m². Diabetes mellitus and hypertension were present in 48% and 79% of patients, respectively (Table 1). The mean corrected serum calcium level was 8.1 ± 0.9 mg/dL, mean serum phosphate 6.2 ± 1.5 mg/dL, mean intact parathyroid hormone 512 ± 236 pg/mL, mean alkaline phosphatase 178 ± 74 IU/L, and mean serum 25-hydroxy vitamin D level 19.6 ± 8.4 ng/mL (Table 2).74 (74%) patients fulfilled the biochemical criteria for chronic kidney disease–mineral and bone disorder (CKD-MBD). The most frequent abnormalities were hyperphosphatemia (68%), elevated intact parathyroid hormone (59%), vitamin D deficiency (57%), elevated alkaline phosphatase (46%), hypocalcemia (41%), and elevated calcium–phosphate product (35%) (Table 3). must never appear in a submitted manuscript.)Patients receiving maintenance hemodialysis for more than three years had a significantly higher prevalence of CKD-MBD than those receiving dialysis for three years or less (84.2% vs. 61.5%; p=0.014). Hyperphosphatemia (78.4% vs. 38.5%; p=0.003) and elevated intact parathyroid hormone (68.9% vs. 30.8%; p<0.001) were also significantly associated with CKD-MBD. No statistically significant associations were observed with age (p=0.287), gender (p=0.451), vitamin D deficiency (p=0.081), or hypocalcemia (p=0.094) (Table 4).

Table 1. Baseline Demographic and Clinical Characteristics of Patients Undergoing Maintenance Hemodialysis (n = 100)

Values are presented as mean ± standard deviation or frequency (percentage). SD = Standard deviation.

Table 2. Biochemical Characteristics of Patients Undergoing Maintenance Hemodialysis (n = 100)

Biochemical parameters were measured before a scheduled hemodialysis session. Values are expressed as mean ± SD.

Table 3. Frequency of Mineral and Bone Disorders Among Maintenance Hemodialysis Patients (n = 100)

Patients may have had more than one biochemical abnormality; therefore, percentages do not total 100%.

Table 4. Univariate Analysis of Factors Associated with CKD–Mineral and Bone Disorder

Associations were evaluated using the Chi-square test for categorical variables and the independent t-test for continuous variables. A p-value <0.05 was considered statistically significant. CKD-MBD = Chronic Kidney Disease–Mineral and Bone Disorder; iPTH = Intact Parathyroid Hormone.

This study revealed that chronic kidney disease–mineral and bone disorder (CKD-MBD) is a common condition among maintenance hemodialysis patients, with 74% of all patients having biochemical markers of mineral and bone abnormalities [10]. The most common results were hyperphosphatemia, secondary hyperparathyroidism, vitamin D deficiency, and hypocalcemia. The findings highlight the importance of CKD-MBD as a persistent complication of CKD, even with the development of various dialysis techniques and pharmacologic treatments. Pathological findings have been noted in recent international studies, which all report CKD-MBD as one of the most prevalent metabolic complications of long-term hemodialysis therapy [11,12]. The overall prevalence of CKD-MBD was similar to that recently reported across South Asia and other developing countries, where the prevalence of CKD-MBD ranges between 65% and 85% in maintenance hemodialysis patients [13]. Another recent study published in the journal Cureus also showed a high prevalence of mineral bone disease, along with biochemical abnormalities, which further highlights the persisting difficulties of achieving KDIGO therapeutic targets [14]. Similarly, abnormalities of serum phosphate and parathyroid hormone are still very common despite regular dialysis care, suggesting that CKD-MBD is not well controlled in many dialysis centers [15]. The higher prevalence observed may reflect inadequate dialysis adequacy, excessive dietary phosphate intake, limited access to phosphate binders, poor medication adherence, and restricted availability of newer therapies. This is in line with recent data demonstrating that an early stage in the progression of advanced CKD is the development of phosphate retention, which is mediated by reduced renal phosphate excretion and directly leads to vascular calcification and cardiovascular morbidity [16]. Improved phosphate control has been linked to better attainment of KDIGO goals and may lower adverse clinical outcomes, according to recent longitudinal studies [17]. Likewise, a recent multicenter study reported secondary hyperparathyroidism in approximately one-third of maintenance hemodialysis patients. In the present study, secondary hyperparathyroidism was observed in 59% of patients, which is consistent with the recent global meta-analysis by Cozzolino et al. In the present study, the prevalence of secondary hyperparathyroidism was 59%, which is similar to the results of a recent global meta-analysis that reported a prevalence rate of almost half of all subjects with CKD, with higher rates in Southern Asia [18]. Fifty-seven percent of patients had a deficiency in vitamin D and 41 percent a calcium deficiency. These abnormalities are closely interconnected since lower levels of calcitriol in the body lead to decreased intestinal calcium uptake, increased parathyroid hormone, and increased bone remodeling. Similar frequencies have been observed in recent observational studies of maintenance hemodialysis patients, which further underscores the need for regular biochemical monitoring and prompt replacement therapy [19]. An important finding of this study was the significant association between CKD-MBD and longer duration of maintenance hemodialysis. The prevalence of CKD-MBD was significantly higher for patients on dialysis for longer than three years compared to those on dialysis for a shorter period of time (p=0.014). Recent cohort and registry studies have found similar relationships, with long-term exposure to chronic mineral metabolism disorders linked to the development of progressive secondary hyperparathyroidism, renal osteodystrophy, and vascular calcification [20]. These are in contrast to age and gender, which were not found to be statistically significant in our study. However, several recent investigations have confirmed that biochemical factors associated with dialysis are more closely related to the development of CKD-MBD than are demographic factors. Limitations The findings might not be generalizable since this study was carried out at a single tertiary care hospital and involved a relatively small number of 100 patients. Its cross-sectional design did not allow for the assessment of causal relationships or long-term outcomes. Due to resource limitations, bone mineral density, bone biopsy, vascular calcification, and fibroblast growth factor-23 (FGF-23) were not assessed.

CKD-MBD is very common in maintenance hemodialysis patients. The most common abnormalities were hyperphosphatemia, secondary hyperparathyroidism, and vitamin D deficiency. To optimize management, minimize skeletal and cardiovascular complications, and maximize outcomes, routine biochemical monitoring, early diagnosis, and following KDIGO recommendations are essential.

Disclaimer: Nil

Conflict of Interest: Nil

Funding Disclosure: Nil

Authors' Contributions

Concept & Design of Study: Humera Bukhari¹,Abrar Uddin²

Data Acquisition: Mazhar-Ul-Haq³,Muhammad

Data Analysis & Interpretation:Muhammad Abbas⁵,Muhammad Arsalan⁶

Drafting of Manuscript:Danyal Najam⁷

Critical Review & Intellectual Content: Baligh-Ur-Rehman Mahmood⁴

Final Approval of the Version to be Published: All authors reviewed and approved the final version of the manuscript and agree to be accountable for all aspects of the work in accordance with the ICMJE authorship criteria.

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