In a large epidemiological study of chronic kidney disease etiology across India, which is the most common cause of CKD in the general population?

Explanation

## Most Common Cause of CKD Globally and in India **Key Point:** Diabetes mellitus is the single most common cause of chronic kidney disease (CKD) worldwide, accounting for approximately 30–40% of all CKD cases globally and an increasing proportion in India. ### Epidemiology of CKD Causes | Rank | Cause | Prevalence (%) | Geographic Variation | |------|-------|---------------|-----------------------| | **1** | **Diabetes mellitus** | **30–40%** | Highest in developed nations; rising in India | | **2** | **Hypertension** | **25–30%** | Varies by region; major in South Asia | | **3** | **Chronic GN** | **10–15%** | Higher in developing countries | | **4** | **Obstructive uropathy** | **5–10%** | Variable; more in endemic stone belt regions | | **5** | **Other/Unknown** | **10–20%** | Includes genetic, autoimmune, drug-induced | **High-Yield:** In the **general population** (not selected hypertensive cohorts), diabetes mellitus is the leading cause of CKD. This reflects: - Rising prevalence of type 2 diabetes in India (>7% of adult population) - Long duration of hyperglycemia before diagnosis - Cumulative nephrotoxic effect of chronic hyperglycemia ### Why Diabetes is the Most Common Cause 1. **Prevalence:** India has the second-largest diabetic population globally (~77 million people) 2. **Duration:** Many patients have undiagnosed diabetes for years before CKD is detected 3. **Pathophysiology:** Hyperglycemia causes glomerular basement membrane thickening, podocyte injury, and progressive glomerulosclerosis 4. **Screening:** Diabetic nephropathy is often detected late, after significant renal damage ### Diabetic Nephropathy: The Hallmark of Diabetic CKD **Mnemonic:** **KDIGO** stages of diabetic CKD: - **K**idney damage (albuminuria) + normal or ↑ GFR - **D**eclining GFR (albuminuria present) - **I**ncreasing albuminuria (GFR declining) - **G**lomerulosclerosis (Kimmelstiel-Wilson lesions) - **O**utcome: ESRD without intervention **Clinical Pearl:** In epidemiological studies, when asked about the "most common cause in the general population," diabetes is the answer. When asked in a specific clinical context (e.g., a hypertensive patient with shrunken kidneys), the answer may be hypertensive nephrosclerosis. ### Distinction from Hypertension While hypertension is a close second and is the most common cause in some hypertensive subpopulations, diabetes remains the leading cause in unselected population-based studies because: - Diabetic patients often have concurrent hypertension (amplifying renal damage) - Diabetes affects a larger proportion of the population than severe hypertension alone - Diabetic nephropathy progresses more rapidly than pure hypertensive disease [cite:Harrison 21e Ch 279; Park 26e Ch 6]