- Enter the patient's body weight in kg.
- Select the insulin requirement category — choose the option that best describes the patient's diabetes type and insulin resistance.
- Select the kidney function tier corresponding to the patient's eGFR. A dose reduction factor is applied automatically: ×0.75 for eGFR 30–59 and ×0.50 for eGFR <30 or dialysis.
- Select the correction-insulin type (rapid-acting uses the Rule of 1800; regular insulin uses the Rule of 1500) for the Insulin Sensitivity Factor.
- Optionally enter the patient's current blood glucose and target glucose to compute a correction dose.
- Results appear automatically. All computation runs in your browser; no values are stored or transmitted.
This tool produces initiation estimates only. Insulin doses must always be individualized and titrated to measured glucose values under physician supervision.
When to Use
Use this tool when initiating insulin therapy in an adult patient with diabetes and CKD (or on dialysis), or when estimating correction factors and carb ratios for a patient whose kidney function has changed. The tool is relevant for type 1 and type 2 DM and covers the full CKD spectrum from eGFR ≥60 down to dialysis-dependent patients.
Appropriate use
Adults (≥18 yr) with type 1 or type 2 diabetes mellitus who are being started on insulin or whose insulin requirements need re-estimation after a change in kidney function. The CKD reduction factor reflects the well-established decrease in renal insulin clearance that accompanies CKD progression — the kidney normally degrades 30–40% of circulating insulin, so as GFR falls, exogenous insulin persists longer and hypoglycemia risk rises.
When NOT to rely on it alone
Do not use these estimates as fixed, standing doses. Insulin requirements change with illness, dietary intake, steroid use, dialysis adequacy, and residual renal function. Patients on dialysis experience acute glucose shifts during and after sessions. Any initiation or change must be followed by frequent self-monitoring of blood glucose (SMBG) or continuous glucose monitoring (CGM) and dose titration. Always consult the full clinical picture and current KDIGO / ADA guidelines.
Pearls & Pitfalls
CKD markedly raises hypoglycemia risk
Renal insulin clearance falls progressively as GFR declines — the kidney normally clears ~30–40% of circulating insulin. In CKD stage 4–5 and on dialysis, insulin half-life is prolonged and carbohydrate intake is often restricted (low-potassium, low-phosphorus diet), so standard doses cause hypoglycemia. Start 25–50% lower than a non-CKD patient of equal weight and titrate slowly. Dialysis patients are at particular risk during and in the 6–8 hours after a hemodialysis session.
Favor basal-dominant regimens in CKD
A basal-only or basal-dominant regimen (≥50% basal, lower bolus) with conservative glucose targets reduces hypoglycemia risk. In non-dialysis CKD stage 4–5, a target fasting glucose of 80–130 mg/dL and a 2-hr postprandial <180 mg/dL are reasonable starting points per KDIGO 2022. In dialysis patients, slightly higher targets (100–140 mg/dL fasting) may be safer — individualize based on hypoglycemia awareness and comorbidities.
Rules of 1800/500 are estimates, not fixed truths
The Rule of 1800 (rapid-acting) and Rule of 1500 (regular) are empirical starting points for the insulin sensitivity factor (ISF). In CKD, because TDD is already reduced, the derived ISF will be larger (each unit drops glucose more), which is clinically appropriate — CKD patients are more sensitive per unit. Use the ISF to guide correction doses only; verify with SMBG before treating and 2–4 hours after. In dialysis, pre-dialysis glucose may rise while post-dialysis glucose can drop sharply.
Insulin requirements often fall with dialysis initiation
Counterintuitively, starting dialysis frequently reduces insulin requirements — uremic toxins impair insulin signaling, so removing them with dialysis can improve insulin sensitivity. Patients who start hemodialysis or peritoneal dialysis may need dose reductions of 25–50% from their pre-dialysis regimen. Monitor closely in the first weeks after dialysis initiation and after any change in dialysis prescription.
Why Use It
Using a non-CKD-adjusted insulin dose in a patient with advanced kidney disease is one of the most common causes of severe hypoglycemia in the nephrology ward and outpatient dialysis setting. Standard weight-based rules (0.3–0.5 u/kg) were derived in patients without significant kidney disease. This tool applies published dose-reduction guidance from KDIGO 2022 and ADA 2024 to produce a safer starting estimate. The basal/bolus split, ISF, and ICR outputs give prescribers a complete starting framework that can be individualized and titrated — rather than guessing from first principles at the bedside.
Insulin Dosing in CKD — Starting Dose, Correction Factor & Carb Ratio Calculator
Enter body weight and select diabetes type, kidney function, and correction-insulin type. Add current and target blood glucose for a correction dose estimate. Results appear automatically.
⚕ TDD = weight(kg) × u/kg/day × CKD-factor. Basal = 50% TDD; Bolus total = 50% TDD; Per-meal bolus = bolus ÷ 3. ISF = Rule ÷ TDD (mg/dL per unit). ICR = 500 ÷ TDD (g carb per unit). Correction dose = round((current − target) ÷ ISF). All values are initiation estimates only — titrate to measured glucose under physician supervision. Never change insulin doses without consulting your care team.
Next Steps
These estimates are a starting framework — not a standing order.
- Begin at the calculated dose and titrate upward (or downward) by 10–20% every 3–7 days based on fasting and postprandial glucose logs.
- Verify the correction dose against the patient's measured glucose before administering; reassess 2–4 hours after any correction.
- In dialysis patients, check pre- and post-dialysis glucose and consider holding or halving the correction dose on dialysis days.
- Educate patients on hypoglycemia symptoms and appropriate treatment (15–15 rule) — especially critical in CKD where hypoglycemia unawareness is more common.
- Review the insulin regimen at every visit, after any change in kidney function, and after starting or stopping dialysis.
- Consider referral to endocrinology or a diabetes care specialist for complex or unstable patients.
Evidence & References
Formula & Equations
| Quantity | Equation |
|---|---|
| Total Daily Dose (TDD) | weight (kg) × insulin requirement (u/kg/day) × CKD reduction factor |
| Basal insulin | 50% × TDD (rounded to nearest whole unit) |
| Total bolus (prandial) | 50% × TDD (rounded) |
| Bolus per meal | Total bolus ÷ 3 (assuming 3 meals/day) |
| Insulin Sensitivity Factor (ISF) | 1800 ÷ TDD (rapid-acting) · or · 1500 ÷ TDD (regular insulin) |
| Insulin-to-Carb Ratio (ICR) | 500 ÷ TDD (g of carbohydrate per 1 unit — Rule of 500) |
| Correction dose | Round((current glucose − target glucose) ÷ ISF) units · only when current > target |
| CKD reduction factor | eGFR ≥60: ×1.0 · eGFR 30–59: ×0.75 · eGFR <30 or dialysis: ×0.50 |
Evidence & References
The CKD dose reduction factors are derived from the observed decrease in renal insulin clearance and the clinical hypoglycemia data reviewed in KDIGO 2022 and ADA 2024. The kidney normally clears 30–40% of circulating insulin; as GFR falls, insulin half-life lengthens and a lower TDD is needed to achieve the same effect. The Rules of 1800 and 1500 are empirical heuristics widely used in diabetes education; in CKD patients the resulting ISF (larger, because TDD is lower) appropriately reflects increased insulin sensitivity per unit. The Rule of 500 for ICR has the same evidence base. All values should be verified against patient-specific glucose logs.
- KDIGO Diabetes Work Group. KDIGO 2022 Clinical Practice Guideline for Diabetes Management in CKD. Kidney Int. 2022;102(5S):S1–S127.
- American Diabetes Association. Standards of Care in Diabetes — 2024. Diabetes Care. 2024;47(Suppl 1).
- Walsh J, Roberts R. Using Insulin (Torrey Pines Press, 2003) — source of the Rules of 1800 and 500.
