Incidence and risk factors of hypertension therapy in Australian cancer patients treated with vascular signalling pathway inhibitors

BACKGROUND: Clinical trials report systemic hypertension is an adverse effect of vascular signalling pathway inhibitor (VSPi) use. There are limited data from routine clinical practice. We aimed to estimate the real-world incidence and risk factors of new-onset and aggravated hypertension for cancer patients dispensed VSPi in whole-of-population Australian setting. METHODS: We used dispensing records for a 10% random sample of Australians to identify treatment with subsidised VSPi from 2013 to 2018. We further identified dispensings of oral antihypertensive medicines 6 months before and 12 months after VSPi therapy. We defined (i) new-onset hypertension in people first dispensed antihypertensives after VSPi and (ii) aggravated hypertension in people with prior antihypertensive use dispensed an additional, or higher strength, antihypertensive after VSPi. We applied the Fine-Gray cumulative incidence function and Cox proportional hazard regression. RESULTS: 1802 patients were dispensed at least one VSPi. The mean age of the cohort was 65 years and 57% were male. The incidence of new-onset treated hypertension was 24.3% (95%CI: 21.2–27.8); age ≥ 60 years (HR 1.74; 95%CI: 1.32–2.31) and treatment with oral tyrosine kinase inhibitors compared to bevacizumab (HR 1.96; 95%CI: 1.16–3.31) were risk factors. The incidence of aggravated hypertension was 25.2% (95%CI: 22.0–28.7) and risk was elevated for patients with renal cancer (HR 2.84; 95%CI: 1.49–5.41) and cancers other than colorectal (HR 1.85; 95%CI: 1.12–3.03). CONCLUSIONS: Our real-world estimates of incident hypertension appear comparable to those observed in clinical trials (21.6–23.6%). Our population-based study provides some insight into the burden of hypertension in patients commencing VSPi in routine practice.