Blood pressure and complications in individuals with type 2 diabetes and no previous cardiovascular disease: national population based cohort studyBMJ 2016; 354 doi: https://doi.org/10.1136/bmj.i4070 (Published 04 August 2016) Cite this as: BMJ 2016;354:i4070
- Samuel Adamsson Eryd, postdoctoral researcher1 2 3,
- Soffia Gudbjörnsdottir, professor1 2,
- Karin Manhem, professor2,
- Annika Rosengren, professor2 3,
- Ann-Marie Svensson, research advisor1,
- Mervete Miftaraj, statistician1,
- Stefan Franzén, senior statistician1,
- Staffan Björck, associate professor1
- 1Centre of Registers Västra Götaland, Gothenburg, Sweden
- 2Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- 3Sahlgrenska University Hospital/Östra Hospital, Gothenburg, Sweden
- Correspondence to: S Adamsson Eryd
- Accepted 15 July 2016
Objectives To compare the risk associated with systolic blood pressure that meets current recommendations (that is, below 140 mm Hg) with the risk associated with lower levels in patients who have type 2 diabetes and no previous cardiovascular disease.
Design Population based cohort study with nationwide clinical registries, 2006-12. The mean follow-up was 5.0 years.
Setting 861 Swedish primary care units and hospital outpatient clinics.
Participants 187 106 patients registered in the Swedish national diabetes register who had had type 2 diabetes for at least a year, age 75 or younger, and with no previous cardiovascular or other major disease.
Main outcome measures Clinical events were obtained from the hospital discharge and death registers with respect to acute myocardial infarction, stroke, a composite of acute myocardial infarction and stroke (cardiovascular disease), coronary heart disease, heart failure, and total mortality. Hazard ratios were estimated for different levels of baseline systolic blood pressure with clinical characteristics and drug prescription data as covariates.
Results The group with the lowest systolic blood pressure (110-119 mm Hg) had a significantly lower risk of non-fatal acute myocardial infarction (adjusted hazard ratio 0.76, 95% confidence interval 0.64 to 0.91; P=0.003), total acute myocardial infarction (0.85, 0.72 to 0.99; P=0.04), non-fatal cardiovascular disease (0.82, 0.72 to 0.93; P=0.002), total cardiovascular disease (0.88, 0.79 to 0.99; P=0.04), and non-fatal coronary heart disease (0.88, 0.78 to 0.99; P=0.03) compared with the reference group (130-139 mm Hg). There was no indication of a J shaped relation between systolic blood pressure and the endpoints, with the exception of heart failure and total mortality.
Conclusions Lower systolic blood pressure than currently recommended is associated with significantly lower risk of cardiovascular events in patients with type 2 diabetes. The association between low blood pressure and increased mortality could be due to concomitant disease rather than antihypertensive treatment.
We thank the regional coordinators, participating nurses, physicians, and other staff members who have contributed to the national diabetes register. Most of all, we thank the patients who support the register, both individually and collectively through the Swedish Diabetes Federation.
Contributors: SAE and SB conceived and designed the study, drafted the manuscript, and are guarantors. SAE, SB, SF, A-MS, and SG expanded on the study concept and design. SG, A-MS, and MM contributed to data collection. SAE, SB, and SF performed the statistical analyses. SF provided statistical expertise. SAE, SB, SF, A-MS, KM, AR, and SG interpreted the data. All authors reviewed and critically revised the draft and approved the final version.
Funding: This study was supported by grants from the Region Västra Götaland in Sweden, the Swedish Heart and Lung Foundation, Diabetes Wellness, the Swedish Diabetes Foundation, the Swedish Council for Working Life and Social Research (Epilife), and the Swedish Research Council.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: The regional ethical review board at the University of Gothenburg approved the study.
Data sharing: No additional data available.
Transparency: The lead authors affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.
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