# Hazard ratio (HR)

Source: https://onco.cc/terms/hazard-ratio/  
OnCo record `hazard-ratio` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A hazard ratio is a number comparing the rate of bad events in two groups. An HR of 0.5 means the risk is halved at any moment.

## Summary

The hazard ratio (HR) is a single number comparing the rate of bad events, such as death or progression, between two groups in a trial; an HR of one half means the risk is halved at any given moment. It comes from Cox proportional hazards models, an HR below 1 favours the experimental arm, and a confidence interval excluding 1 indicates statistical significance. The HR says nothing about absolute benefit or how long it lasts, so it features in ideas on powering trials for a benefit patients would value, crossover-adjusted survival and Bayesian shrinkage for subgroup claims. The term is referenced by the Pancreatic ductal adenocarcinoma entry, Michael LeBlanc, the bottlenecks on trial design and trial diversity, and ideas on Bayesian borrowing and a rulebook for external control arms.

## Fields

- Kind: Term
- Last checked: 2026-09-04
- Also known as: HR 0; HR 1; HR of; HR for death; HR for progression; HR for recurrence; HRs; Cox proportional hazards; proportional hazards

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Hazard_ratio
- Wikipedia: https://en.wikipedia.org/wiki/Hazard_ratio

## Connected records

- terms: [Absolute versus relative benefit (number needed to treat)](https://onco.cc/terms/absolute-benefit/), [C-index (concordance index), Harrell's and Uno's](https://onco.cc/terms/concordance-index/), [Censoring and events in survival data](https://onco.cc/terms/censoring-and-events/), [Clinical benefit response (the gemcitabine trial endpoint)](https://onco.cc/terms/clinical-benefit-response/), [Confidence interval](https://onco.cc/terms/confidence-interval/), [Crossover in trials](https://onco.cc/terms/crossover/), [Data maturity (immature vs mature survival data)](https://onco.cc/terms/data-maturity/), [Endpoint](https://onco.cc/terms/endpoint/), [Intermittent androgen deprivation (IAD)](https://onco.cc/terms/intermittent-androgen-deprivation/), [Kaplan-Meier curve, censoring and proportional hazards](https://onco.cc/terms/kaplan-meier-curve/), [Landmark and milestone survival (5-year survival, median follow-up)](https://onco.cc/terms/landmark-survival/), [Median survival](https://onco.cc/terms/median-survival/), [Metastasis-free survival (MFS)](https://onco.cc/terms/metastasis-free-survival/), [Number needed to screen (and number needed to diagnose)](https://onco.cc/terms/number-needed-to-screen/), [Other-cause mortality](https://onco.cc/terms/other-cause-mortality/), [Overall survival (OS)](https://onco.cc/terms/os/), [P-value](https://onco.cc/terms/p-value/), [Pancreatic cancer: the failed and stopped programmes and why](https://onco.cc/terms/pancreatic-failed-programmes/), [Progression-free survival (PFS)](https://onco.cc/terms/pfs/), [Radiographic progression-free survival (rPFS)](https://onco.cc/terms/radiographic-progression-free-survival/), [Randomised trial](https://onco.cc/terms/randomised-trial/), [Reading a hazard ratio](https://onco.cc/terms/hazard-ratio-basics/), [Statistical power, sample size and re-estimation](https://onco.cc/terms/sample-size-re-estimation/), [Statistical significance (P values, alpha, multiplicity)](https://onco.cc/terms/statistical-significance/), [Univariate Cox scores and time-dependent metrics](https://onco.cc/terms/time-dependent-auc/)
- trials: [ADAURA](https://onco.cc/trials/adaura/), [ASPREE (ASPirin in Reducing Events in the Elderly)](https://onco.cc/trials/aspree/), [CHALLENGE (CCTG CO.21)](https://onco.cc/trials/challenge/), [CheckMate 067](https://onco.cc/trials/checkmate-067/), [VITAL (VITamin D and OmegA-3 TriaL)](https://onco.cc/trials/vital/)
- cancers: [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- key papers: [Adjuvant Capecitabine for Breast Cancer after Preoperative Chemotherapy](https://onco.cc/key-papers/paper-create-x-adjuvant-capecitabine-nejm-2017/), [Association of Black race with prostate cancer-specific and other-cause mortality](https://onco.cc/key-papers/paper-dess-black-race-prostate-mortality-jama-oncol-2019/), [Association of Circulating Tumor DNA and Circulating Tumor Cells After Neoadjuvant Chemotherapy With Disease Recurrence in Patients With Triple-Negative Breast Cancer: Preplanned Secondary Analysis of the BRE12-158 Randomized Clinical Trial](https://onco.cc/key-papers/paper-radovich-ctdna-ctc-bre12-158-jama-oncol-2020/), [CheckMate 067 at ten years: nivolumab plus ipilimumab produces long-term survival in half of patients with advanced melanoma](https://onco.cc/key-papers/paper-checkmate-067-10-year-nejm-2025/), [Five-Year Outcomes of FOLFIRINOX vs Gemcitabine as Adjuvant Therapy for Pancreatic Cancer: A Randomized Clinical Trial](https://onco.cc/key-papers/paper-prodige-24-five-year-outcomes-jama-oncol-2022/), [GETUG-AFU 15: androgen deprivation alone or with docetaxel in non-castrate metastatic prostate cancer](https://onco.cc/key-papers/paper-gravis-getug-afu-15-docetaxel-lancet-oncol-2013/), [monarchE: two years of abemaciclib after surgery in high-risk, hormone-receptor-positive early breast cancer](https://onco.cc/key-papers/paper-monarche-jco-2020/), [Nanoliposomal irinotecan with fluorouracil and folinic acid in metastatic pancreatic cancer after previous gemcitabine-based therapy (NAPOLI-1): a global, randomised, open-label, phase 3 trial](https://onco.cc/key-papers/paper-napoli-1-nanoliposomal-irinotecan-lancet-2016/), [NATALEE: three years of ribociclib after surgery in a broad population of hormone-receptor-positive early breast cancer](https://onco.cc/key-papers/paper-natalee-nejm-2024/), [Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer](https://onco.cc/key-papers/paper-olympia-overall-survival-ann-oncol-2022/), [Pathological complete response and long-term clinical benefit in breast cancer: the CTNeoBC pooled analysis](https://onco.cc/key-papers/paper-cortazar-ctneobc-pcr-pooled-analysis-lancet-2014/), [PD-L1 Immunohistochemistry Assay Comparison in Atezolizumab Plus nab-Paclitaxel-Treated Advanced Triple-Negative Breast Cancer](https://onco.cc/key-papers/paper-rugo-pd-l1-assay-comparison-impassion130-jnci-2021/), [Prasad: most surrogate endpoints in cancer trials correlate poorly with survival](https://onco.cc/key-papers/paper-prasad-surrogate-endpoints-jama-im-2015/), [Residual cancer burden after neoadjuvant chemotherapy and long-term survival outcomes in breast cancer: a multicentre pooled analysis of 5161 patients](https://onco.cc/key-papers/paper-yau-rcb-pooled-analysis-5161-lancet-oncol-2022/), [STOpCaP: docetaxel or bisphosphonates added to standard of care in hormone-sensitive prostate cancer, a systematic review and meta-analysis](https://onco.cc/key-papers/paper-vale-stopcap-docetaxel-bisphosphonates-lancet-oncol-2016/), [Survival analysis of carboplatin added to an anthracycline/taxane-based neoadjuvant chemotherapy and HRD score as predictor of response-final results from GeparSixto](https://onco.cc/key-papers/paper-loibl-geparsixto-survival-hrd-ann-oncol-2018/), [SWOG 9346: intermittent versus continuous androgen deprivation in metastatic prostate cancer](https://onco.cc/key-papers/paper-hussain-swog-9346-intermittent-androgen-deprivation-nejm-2013/), [TAX 327: docetaxel plus prednisone or mitoxantrone plus prednisone for advanced prostate cancer](https://onco.cc/key-papers/paper-tannock-tax-327-docetaxel-prednisone-nejm-2004/), [The Multicenter Cancer of Pancreas Screening Study: Impact on Stage and Survival](https://onco.cc/key-papers/paper-dbouk-caps5-stage-survival-jco-2022/), [Triple-negative breast cancer: clinical features and patterns of recurrence](https://onco.cc/key-papers/paper-dent-tnbc-clinical-features-recurrence-ccr-2007/), [TROPIC: prednisone plus cabazitaxel or mitoxantrone for metastatic castration-resistant prostate cancer progressing after docetaxel](https://onco.cc/key-papers/paper-de-bono-tropic-cabazitaxel-lancet-2010/), [Tumor-Infiltrating Lymphocytes in Triple-Negative Breast Cancer](https://onco.cc/key-papers/paper-leon-ferre-tils-tnbc-no-chemotherapy-jama-2024/)
- ideas: [A pre-registered standard for emulating trials with real-world data](https://onco.cc/ideas/idea-data-target-trial-emulation-standard/), [A public rulebook for when an external or synthetic control arm is acceptable](https://onco.cc/ideas/idea-tr1-external-control-rulebook/), [Agree in advance how to borrow evidence between similar rare cancers](https://onco.cc/ideas/idea-bio2-bayesian-borrowing-acceptance/), [Bayesian shrinkage for subgroup claims to stop false 'works in this group' stories](https://onco.cc/ideas/idea-tr1-shrinkage-subgroup-analysis/), [Borrow from past control arms to shrink the control group in phase 3](https://onco.cc/ideas/idea-tr1-bayesian-borrowing-smaller-controls/), [Deposit trial results as structured data, not just PDFs](https://onco.cc/ideas/idea-data-structured-trial-results-deposit/), [Power trials to detect a benefit patients would value, not the smallest detectable one](https://onco.cc/ideas/idea-tr1-power-for-meaningful-benefit/), [Pre-specified crossover-adjusted survival in every trial that allows crossover](https://onco.cc/ideas/idea-tr1-crossover-adjusted-survival-standard/), [Publish the disagreement between trial doctors and independent reviewers for every trial](https://onco.cc/ideas/idea-tr2-bicr-discordance-public/), [Quality-adjusted survival reported in every trial publication and label](https://onco.cc/ideas/idea-moon-quality-adjusted-survival-standard/), [Report gallbladder cancer as its own population in every biliary trial](https://onco.cc/ideas/idea-gbc-report-gallbladder-separately-in-biliary-trials/), [Shared concurrent control arms across sponsors' trials in the same setting](https://onco.cc/ideas/idea-tr2-shared-control-network/), [Test the drug in biomarker-negative patients too, so the biomarker can be validated](https://onco.cc/ideas/idea-tr2-marker-stratified-default/)
- people: [Michael LeBlanc](https://onco.cc/people/michael-leblanc/)
- bottlenecks: [Older and multimorbid patients are excluded and undertreated](https://onco.cc/bottlenecks/b-aging-comorbidity/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/), [Trial design, endpoints and cost](https://onco.cc/bottlenecks/b-trial-design/), [Trials do not represent the people who get cancer](https://onco.cc/bottlenecks/b-trial-diversity/)
- collections: [NICE cancer guidance and technology appraisals (UK)](https://onco.cc/collections/nice-guidance/)
- institutions: [Gemeinsamer Bundesausschuss / IQWiG](https://onco.cc/institutions/g-ba-iqwig/), [ISPOR (The Professional Society for Health Economics and Outcomes Research)](https://onco.cc/institutions/ispor/), [National Institute for Health and Care Excellence](https://onco.cc/institutions/nice/), [Vivli](https://onco.cc/institutions/vivli/)

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