Cancer incidence following platelet count and C-reactive protein testing across ethnic groups in English primary care: a cohort study of 5 million patients
4 affiliations
- 1Department of Health and Community Sciences, St Luke’s Campus, University of Exeter, Exeter, UK
- 2Centre for Primary Care & Health Services Research, The University of Manchester, Manchester, UK
- 3Centre for Academic Primary Care (CAPC), Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- 4Department of Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Abstract
Objectives: To investigate whether the association between platelet count or C-reactive protein (CRP) results and 1-year cancer incidence varies by patient ethnicity.
Design: Cohort study using routinely collected health records from the Clinical Practice Research Datalink Aurum, Hospital Episode Statistics Admitted Patient Care and National Cancer Registration and Analysis Service.
Setting: English primary care, with linkage to secondary care records and national cancer registry data.
Participants: Patients aged 40 years or older with a recorded ethnicity, no previous malignancy, and a platelet count or CRP test recorded between 1 January 2010 and 31 December 2017. Ethnicity was categorised as white, Asian, black, other or mixed.
Primary and secondary outcome measures: The primary outcome measures were 1-year cancer incidence following platelet count or CRP testing and variation in the association by ethnicity. Secondary outcome measures were 1-year site-specific cancer incidence and stage at diagnosis.
Results: The study included 4 901 450 patients with a platelet count record and 811 559 with a CRP record. One-year cancer incidence was highest among white patients and lowest among Asian patients. Following a normal platelet count, 1-year cancer incidence was 1.3% (95% CI 1.3 to 1.3%) for white patients and 0.63% (0.60 to 0.66%) for Asian patients; following thrombocytosis, incidence increased to 3.9% (3.8 to 4.0%) and 1.8% (1.5 to 2.1%), respectively. After a normal CRP result, cancer incidence was 1.5% (1.4 to 1.5%) for white patients and 0.81% (0.73 to 0.90%) for Asian patients, rising to 3.6% (3.5 to 3.7%) and 1.9% (1.7 to 2.2%) for a high CRP result, respectively. No significant interactions were found between ethnicity, blood test result and overall cancer diagnosis, and similar ORs were observed across all ethnic groups. However, for colorectal cancer, black patients with abnormal results showed higher ORs compared with white patients, relative to a normal result. The OR for thrombocytosis was 11.1 (7.8 to 15.6) for black patients versus 5.7 (5.4 to 6.0) for white patients (interaction p value<0.001), and for raised CRP was 4.1 (2.6 to 6.6) for black patients versus 2.5 (2.3 to 2.7) for white patients (interaction p value=0.043).
Conclusions: This large primary care study provides reassurance that thrombocytosis and raised CRP appear to have broadly consistent associations with 1-year cancer incidence across ethnic groups in UK primary care.
Related
- C-reactive Protein-to-Albumin Ratio for Evaluating Patients with Chronic Limb-Threatening Ischemia Following Endovascular Therapy
- High sensitivity-C-reactive protein variability and risk of cancer incidence: A longitudinal prospective cohort study cancer
- The Impact of Idiopathic Pulmonary Fibrosis on the Incidence and Severity of Radiation Pneumonitis in Non-Small Cell Lung Cancer Patients Following Radiotherapy
- Association of admission C-reactive protein levels and histological chorioamnionitis in patients with preterm premature rupture of membranes: a systematic review and meta-analysis
- Prognostic Value of the C-Reactive Protein-to-Albumin Ratio in Patients Hospitalized with Atrioventricular Block: Association with In-Hospital Mortality and Temporary Pacemaker Requirement
BibTeX
@article{barlow2026cancer,
title = {{Cancer incidence following platelet count and C-reactive protein testing across ethnic groups in English primary care: a cohort study of 5 million patients}},
author = {Melissa Barlow and Liz Down and Luke T A Mounce and Samuel W D Merriel and Jessica Watson and Tanimola Martins and Sarah E R Bailey},
journal = {BMJ Open},
year = {2026},
month = oct,
doi = {10.1136/bmjopen-2026-120128},
url = {https://bmjopen.bmj.com/lookup/doi/10.1136/bmjopen-2026-120128},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Cancer incidence following platelet count and C-reactive protein testing across ethnic groups in English primary care: a cohort study of 5 million patients
AU - Melissa Barlow
AU - Liz Down
AU - Luke T A Mounce
AU - Samuel W D Merriel
AU - Jessica Watson
AU - Tanimola Martins
AU - Sarah E R Bailey
PY - 2026
DA - 2026/10/26
JO - BMJ Open
DO - 10.1136/bmjopen-2026-120128
UR - https://bmjopen.bmj.com/lookup/doi/10.1136/bmjopen-2026-120128
AB - Objectives: To investigate whether the association between platelet count or C-reactive protein (CRP) results and 1-year cancer incidence varies by patient ethnicity. Design: Cohort study using routinely collected health records from the Clinical Practice Research Datalink Aurum, Hospital Episode Statistics Admitted Patient Care and National Cancer Registration and Analysis Service. Setting: English primary care, with linkage to secondary care records and national cancer registry data. Participants: Patients aged 40 years or older with a recorded ethnicity, no previous malignancy, and a platelet count or CRP test recorded between 1 January 2010 and 31 December 2017. Ethnicity was categorised as white, Asian, black, other or mixed. Primary and secondary outcome measures: The primary outcome measures were 1-year cancer incidence following platelet count or CRP testing and variation in the association by ethnicity. Secondary outcome measures were 1-year site-specific cancer incidence and stage at diagnosis. Results: The study included 4 901 450 patients with a platelet count record and 811 559 with a CRP record. One-year cancer incidence was highest among white patients and lowest among Asian patients. Following a normal platelet count, 1-year cancer incidence was 1.3% (95% CI 1.3 to 1.3%) for white patients and 0.63% (0.60 to 0.66%) for Asian patients; following thrombocytosis, incidence increased to 3.9% (3.8 to 4.0%) and 1.8% (1.5 to 2.1%), respectively. After a normal CRP result, cancer incidence was 1.5% (1.4 to 1.5%) for white patients and 0.81% (0.73 to 0.90%) for Asian patients, rising to 3.6% (3.5 to 3.7%) and 1.9% (1.7 to 2.2%) for a high CRP result, respectively. No significant interactions were found between ethnicity, blood test result and overall cancer diagnosis, and similar ORs were observed across all ethnic groups. However, for colorectal cancer, black patients with abnormal results showed higher ORs compared with white patients, relative to a normal result. The OR for thrombocytosis was 11.1 (7.8 to 15.6) for black patients versus 5.7 (5.4 to 6.0) for white patients (interaction p value<0.001), and for raised CRP was 4.1 (2.6 to 6.6) for black patients versus 2.5 (2.3 to 2.7) for white patients (interaction p value=0.043). Conclusions: This large primary care study provides reassurance that thrombocytosis and raised CRP appear to have broadly consistent associations with 1-year cancer incidence across ethnic groups in UK primary care.
SN - 2044-6055
SN - 2044-6055
ER -