Tinzaparin, an alternative to subcutaneous unfractionated heparin, in patients with severe and end-stage renal impairment: a retrospective observational single-center study.

Background: Tinzaparin could be easier to manage than unfractionated heparin in patients with severe renal impairment. However, clinical and pharmacologic data regarding its use in such patients are lacking.

Objectives: The aims of this study were to determine, in patients with estimated glomerular filtration rate (eGFR) of <30 mL.min⁻, tinzaparin pharmacokinetics (PK) parameters using a population PK approach and bleeding and thrombotic complications.

Methods: We performed a retrospective observational single-center study, including in-patients with eGFR of <30 mL.min⁻ receiving prophylactic (4500 IU.d⁻) or therapeutic (175 IU.kg⁻.d⁻) tinzaparin. Measured anti-Xa levels were analyzed using a nonlinear mixed-effects modeling approach. Individual predicted tinzaparin exposure markers at steady state were calculated for each patient and dosing regimen. The PK was also evaluated through Monte Carlo simulations based on the final covariate model parameter estimates.

Results: Over a 22-month period, 802 tinzaparin treatment periods in 623 patients were analyzed: two-thirds received a prophylactic dose, 66% had an eGFR of <20 mL.min⁻, and 25% were on renal replacement therapy. In patients for whom anti-Xa measurements were performed (n = 199; 746 values), PK parameters, profiles, and maximum plasma concentrations were comparable with those in patients without renal impairment or in healthy volunteers. In the whole population, major bleeding occurred in 2.4% and 3.5% of patients receiving prophylactic and therapeutic doses over a median 9- and 7-day treatment period, respectively. No patients had thrombotic complications.

Conclusion: Tinzaparin PK parameters and profiles were not affected by renal impairment. This suggests that tinzaparin, at therapeutic or prophylactic dose, could be an alternative to unfractionated heparin in hospitalized patients with severe renal impairment.