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# Kidney transplant recipients with polycystic kidney disease clot more, and their higher hemoglobin is part of the explanation
- URL: https://nephspace.com/adpkd-transplant-venous-thromboembolism/
- Published: 2026-11-02T11:56:00.000Z
- Updated: 2026-11-02T11:55:59.000Z
- Description: In two transplant cohorts totaling 5,594 recipients, venous thromboembolism was more common with ADPKD: 21.0% versus 15.1% at 10 years in the Swiss cohort. The excess was concentrated in the first two years and in men, and accounting for hemoglobin over time weakened the association.
- Author: Dr Wael Hussein
- Tags: Other, #story, #has-audio, #research, #full-story, #transplant, #genetics-cystic, Stories

**🎧 Listen:** [Weekly · Nov 2](https://nephspace.com/weekly-nov-2/), from 01:28.

### The question

Kidney transplant recipients are already at raised risk of venous thromboembolism, and ADPKD has been suspected of raising it further. Two mechanisms are plausible: the native polycystic kidneys continue to produce erythropoietin after transplantation, and enlarged kidneys may compress the inferior vena cava. The 2025 KDIGO guideline offers no disease-specific guidance on prevention.

### What the study did

An observational study of first kidney transplant recipients at the University Medical Center Groningen (1,179 recipients, 393 with ADPKD, transplanted 2008 to March 2025), with key analyses replicated in the Swiss Transplant Cohort Study (4,415 recipients, 710 with ADPKD, 2008 to 2023). The primary endpoint was time to first imaging-confirmed deep vein thrombosis or pulmonary embolism, or death attributed to venous thromboembolism, identified by medical record review. Cox models adjusted for sex, age, BMI, smoking, prior venous thromboembolism, atrial fibrillation and anticoagulant use. Median follow-up was about six years.

### What they found

- Venous thromboembolism was more common with ADPKD in both cohorts: 12.0% vs 8.1% in Groningen (p=0.04) and 16.5% vs 11.0% in Switzerland (p<0.001).
- Ten-year cumulative incidence: 13.5% vs 9.6% in Groningen, and 21.0% vs 15.1% in Switzerland.
- Risk was highest in the first two years; median time to the event was about 1.4 to 1.7 years.
- After adjustment, ADPKD remained associated with venous thromboembolism: hazard ratio 1.80 (95% CI, 1.21 to 2.69) in Groningen and 1.39 (1.13 to 1.72) in Switzerland. Prior venous thromboembolism was the strongest predictor in both.
- The excess applied to deep vein thrombosis (HR 1.48) and to pulmonary embolism (HR 1.61). Pulmonary embolism was associated with higher mortality, and both with graft loss.
- **Hemoglobin:** in 2,010 recipients with measurements, those with ADPKD ran about 7% higher hemoglobin at every time point through 10 years, and were more likely to develop erythrocytosis (odds ratio 3.31). Venous thromboembolism risk climbed steeply at erythrocytosis-range hemoglobin levels.
- Adding hemoglobin over time as a time-varying covariate attenuated the association with ADPKD (pooled HR from 1.43 to 1.32, no longer significant), which the authors interpret as hemoglobin at least partly mediating the excess risk.
- The association was concentrated in men (interaction p=0.02); in women there was no clear difference. Pre-transplant native nephrectomy showed no clear protection.

### Why it matters

There is no venous thromboembolism risk tool for kidney transplant recipients. The authors note that oncology guidelines consider primary thromboprophylaxis when the estimated six-month risk exceeds 8%, and suggest that ADPKD recipients with additional risk factors, such as prior venous thromboembolism, mTOR inhibitor use, surgery or prolonged immobilization, may reach clinically relevant thresholds. They call for individualized risk assessment and studies of prevention.

Our take: in a man with polycystic kidney disease in the first two years after transplant, put clots on the radar early, and watch the hemoglobin. Note that this paper concerns erythropoietin from the native polycystic kidneys, not SGLT2 inhibitors, although both stories this week point in the same direction.

### Caveats

Retrospective, with events identified from imaging and clinical records, so subclinical events will have been missed. Data on perioperative factors and post-transplant anticoagulation were limited, and kidney and liver volumes were unavailable. This is an association, not proof of cause.

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**The source:** Bais T, Alnaim AA, Tegzess E, et al. Risk of Venous Thromboembolism in Kidney Transplant Recipients with Autosomal Dominant Polycystic Kidney Disease. J Am Soc Nephrol. Published online October 26, 2026\. doi:10.1681/ASN.0000001298 [Read the original](https://doi.org/10.1681/ASN.0000001298?ref=nephspace.com)

**🎧 Listen:** [Weekly · Nov 2](https://nephspace.com/weekly-nov-2/), from 01:28.

*Physician-led, AI-assisted. Dr. Wael Hussein chooses every item NephSpace covers and reviews and edits every story before it is published. The first draft was written in our own words with AI (Claude, by Anthropic) from the full text of the paper and checked against our reading notes; Dr. Hussein then reviewed and edited it. For education and information only, not medical advice. Please talk to your own physician or care team about your health. Clinicians: read the original before changing practice. See our* [*disclaimer*](https://nephspace.com/disclaimer/) *and* [*disclosures*](https://nephspace.com/disclosures/)*. Spotted an error?* [*Tell us*](mailto:hello@nephspace.com?subject=Correction)*.*