Chronic kidney disease (CKD) has been described as a silent epidemic of the twenty-first century, affecting as many as 16% of the adult population1. In India alone, over one hundred thousand people are diagnosed with CKD each year, requiring dialysis or transplantation, and patients with end-stage renal disease (ESRD) frequently carry comorbidities such as diabetes and cardiovascular disease. Among the non-renal chronic disorders encountered in ESRD, gastrointestinal disease is the most common2. CKD encompasses a spectrum of pathophysiological processes characterised by abnormal kidney function and a progressive decline in glomerular filtration rate (GFR), staged by estimated GFR and the degree of albuminuria. The resulting accumulation of nitrogenous waste products and disturbance of internal homeostasis affects virtually every organ system, including the gastrointestinal tract. Gastrointestinal symptoms are common in CKD, though their type and frequency vary across geographic regions and correlate with the degree of renal impairment3–5. As serum creatinine rises and GFR falls, symptoms such as anorexia, nausea, vomiting, hiccups, epigastric pain, regurgitation, dyspepsia, heartburn, dysphagia and haematemesis become more frequent, often reflecting underlying mucosal disease — duodenal ulcer, angiodysplasia, oesophagitis, gastric erosions and hiatus hernia. Among upper gastrointestinal (UGI) lesions in CKD, gastritis, oesophagitis and gastric ulcer are the most prevalent and UGI bleeding is reported to cause death in 3–7% of CKD patients1. These lesions are more common in advanced CKD and can markedly impair quality of life. Reported prevalence rates of UGI lesions in CKD vary widely between populations — 72.9% in Burkina Faso3 and 74–90% in Italy4, for instance — underscoring the need for region-specific data. Several studies have shown that early diagnosis and management of these lesions can reduce associated mortality and morbidity. This study was undertaken to characterise upper gastrointestinal changes on endoscopy in patients with CKD attending a tertiary care centre in Karnataka and to evaluate their relationship with CKD stage. Objectives 1. To determine the prevalence of various upper gastrointestinal lesions using fibre-optic endoscopy in patients with chronic kidney disease. 2. To evaluate the relationship between upper gastrointestinal lesions and the stage of CKD / GFR.

Study design and setting: This was a cross-sectional observational study conducted in the Department of General Medicine at Subbaiah Medical College, Shimoga, over a 1-year period. Study population: A total of 50 adult patients (age > 18 years) diagnosed with CKD, presenting to the outpatient department or admitted to the hospital, and fulfilling the inclusion criteria, were enrolled. Sample size was calculated based on a reference prevalence of upper gastrointestinal endoscopic lesions in CKD of 76% and a permissible error of 16%; the enrolled cohort of 50 subjects met this requirement. Inclusion criteria: Adult patients (> 18 years) diagnosed with chronic kidney disease. Exclusion criteria: Patients with a history of acid-peptic disease; patients on long-term high-dose NSAIDs; patients with cirrhosis of the liver and oesophageal varices; patients with a history of chronic alcoholism, chronic smoking or chronic tobacco chewing; and patients diagnosed with acute kidney injury (AKI) were excluded. Diagnosis and staging of CKD: CKD was diagnosed on the basis of uraemic symptoms persisting for three months or more, elevated blood urea and serum creatinine with reduced creatinine clearance, ultrasonographic evidence of CKD (bilaterally contracted kidneys, poor corticomedullary differentiation, or grade 2–3 renal parenchymal changes), and supportive laboratory findings such as anaemia and electrolyte disturbance. CKD stage was calculated from estimated GFR using the Cockcroft-Gault formula. Clinical evaluation and investigations: Detailed clinical history and examination were undertaken with particular reference to gastrointestinal and renal complaints. Investigations performed in all patients included haemoglobin, total leucocyte count and ESR, random blood sugar, blood urea and serum creatinine, serum electrolytes, urine analysis and electrocardiography. Endoscopy: All enrolled patients underwent upper gastrointestinal endoscopy using a flexible fibre-optic endoscope (Olympus Inc.), and endoscopic findings were recorded and correlated with CKD stage, sex, and mode of treatment (haemodialysis versus conservative management). Statistical analysis: Data were tabulated and analysed using SPSS version 16.0. Results are expressed as frequencies and percentages

A total of 50 patients diagnosed with chronic kidney disease were studied over a 1-year period. GFR and endoscopic findings were tabulated and analysed for each subject. Age and sex distribution Patients ranged in age from 19 to 80 years. The largest proportion (26%) was in the 31–40-year age group, and the smallest (6%) was in the 70–80-year age group. Of the 50 patients, 28 (56%) were male, and 22 (44%) were female. Table 1. Age distribution of study subjects. 19–30 6 12 31–40 13 26 41–50 8 16 51–60 12 24 61–70 8 16 70–80 3 6 Total 50 100 CKD stage distribution No patient in the cohort belonged to CKD stage I. Stage IV was the most common stage (44%), followed by stage V (30%), stage IIIA (12%), stage IIIB (10%) and stage II (4%). Prevalence and pattern of upper gastrointestinal lesions Of the 50 patients, 42 (84%) had an abnormal upper gastrointestinal endoscopic finding; the remaining 8 (16%) had a normal study. Erosive gastritis was the single most common lesion, followed by gastro-oesophageal reflux disease (GERD) with or without duodenitis. Table 2. Upper gastrointestinal endoscopic findings in CKD patients (n = 50). Erosive gastritis 13 26 GERD with/without duodenitis 10 20 Duodenal ulcer 4 8 Gastric ulcer 4 8 Pan-gastritis 3 6 GERD with gastritis 2 4 Erosive oesophagitis 2 4 Pale gastric mucosa 2 4 Angiodysplasia of stomach 1 2 Hiatus hernia 1 2 Normal study 8 16 Site of involvement Among the 42 patients with an abnormal endoscopy, the stomach was the most frequently affected site (55%), followed by the duodenum (26%) and the oesophagus (19%). Table 3. Site of upper gastrointestinal involvement. Stomach 23 55 Duodenum 11 26 Oesophagus 8 19 Total 42 100 Lesions in relation to CKD stage The prevalence and severity of UGI lesions increased with advancing CKD stage. Overall, UGI involvement was seen in 54.5% of stage III patients, 95% of stage IV patients and 100% of stage V patients; the two patients in stage II had no endoscopic abnormality. Erosive gastritis, the predominant lesion, occurred mainly in stage IV (53.8%) and stage V (30.7%) patients, with 15% in stage III. GERD, with or without duodenitis, followed a similar stage-wise gradient (stage III, 10%; stage IV, 60%; stage V, 30%). Duodenal ulcer, gastric ulcer, GERD with gastritis and pan-gastritis were likewise concentrated in stages IV and V. Mode of treatment Of the 50 patients, 26 (52%) were on maintenance haemodialysis, and 24 (48%) were managed conservatively. Nearly all patients in stage V were on haemodialysis. UGI lesions were more prevalent in the haemodialysis group (25/26, 96.1%) than in the conservatively managed group (17/24, 70.8%).

Chronic kidney disease is associated with abnormalities of the gastrointestinal tract involving all its segments, broadly falling into two categories: gastro-oesophageal dysmotility (delayed gastric emptying and reflux) and mucosal lesions such as oesophagitis, gastritis and peptic ulcer arising as a consequence of uraemia. The present study, involving 50 patients with CKD who underwent upper gastrointestinal endoscopy together with relevant biochemical and imaging work-up, found a high prevalence of endoscopic abnormalities (84%). This prevalence is broadly consistent with earlier reports, though there is considerable variation across studies — 86% in a study by Goyal et al.1, 68% by Sreelatha et al.5, 79% by Khedmat et al.6, 90% by Nardone et al.4, 90.7% by Al-Mueilo7, 95.7% by Agarwal and Srivastava8 and 72% by Varma et al.9. Differences in patient selection, endoscopic criteria and background prevalence of Helicobacter pylori infection likely account for this variability. The age distribution in this cohort (19–80 years, predominantly 31–40 years) was comparable to that reported by Sreelatha et al. (14–80 years, predominantly 21–40 years)5 and by Varma et al. (17–70 years)9. Erosive gastritis, the predominant lesion in this study (26%), has also been the leading finding in several other series, although the reported figure varies — 27% in Varma et al.9, 16% in Sreelatha et al.5, 60.8% (as gastritis) in Esfahani et al.10, 68% in Goyal et al.1, 57% in Al-Mueilo7 and 32% in Nand et al.2. Elevated gastrin levels, Helicobacter pylori infection, and the toxic effects of urea and related nitrogenous compounds on the gastric mucosa are the mechanisms most often implicated in the pathogenesis of erosive gastritis in CKD. Site-wise, the stomach was the most commonly involved organ in this study (55%), followed by the duodenum (26%) and oesophagus (19%) — a pattern broadly mirrored by Nardone et al. (56% gastric, 36% duodenal, 18% oesophageal)4 and Goyal et al. (gastritis 68%, oesophagitis 42%, duodenitis 8%)1, although the relative ranking of duodenal versus oesophageal involvement differed between studies, for instance in Sreelatha et al. where the oesophagus (29%) was more frequently involved than the duodenum (23%)5. A clear gradient of increasing UGI involvement with advancing CKD stage was observed — 54.5% in stage III, rising to 95% in stage IV and 100% in stage V. A comparable stage-wise gradient has been reported by Sreelatha et al. (83.3% in stage III, 57% in stage IV, 70% in stage V)5 and by Goyal et al., who additionally observed that gastritis was more common and more severe in stage V (88% of gastritis cases) than in stage IV (12%)1. This gradient is consistent with a cumulative, dose-related effect of uraemic toxins on the gastric and duodenal mucosa as renal function declines. UGI lesions were also more prevalent among patients on haemodialysis (96.1%) than among those managed conservatively (70.8%) in this study, a difference also reported by Sreelatha et al. (69.2% in the haemodialysis group versus 61.1% in the conservatively managed group)5. Contributing factors may include the longer disease duration and more advanced CKD stage typical of dialysis-dependent patients, as well as the physiological stress of the dialysis procedure itself, including the risk of heparin-related mucosal bleeding and haemodynamic shifts during sessions. Taken together, these findings reinforce the case for a low threshold to perform upper gastrointestinal endoscopy in symptomatic CKD patients, particularly those with advanced disease (stage IV/V) or those established on haemodialysis, given the high burden of mucosal pathology and the attendant risk of UGI haemorrhage in this group.

1. The majority of patients with chronic kidney disease have upper gastrointestinal involvement on endoscopic evaluation. 2. Erosive gastritis is the most common upper gastrointestinal manifestation. 3. Upper gastrointestinal manifestations are most frequent and severe in CKD stage V. 4. Upper gastrointestinal findings are more frequently observed in CKD patients on haemodialysis than in those managed conservatively. 5. Early diagnosis and appropriate management of these lesions may help reduce morbidity and mortality and prevent complications such as massive upper gastrointestinal bleeding.

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