title: Hypertension: a cross-sectional study of the role of multimorbidity in blood pressure control.
abstract: BACKGROUND
  Hypertension is the most prevalent cardiovascular long-term condition in the UK and is associated with a high rate of multimorbidity (MM). Multimorbidity increases with age, ethnicity and social deprivation. Previous studies have yielded conflicting findings about the relationship between MM and blood pressure (BP) control. Our aim was to investigate the relationship between multimorbidity and systolic blood pressure (SBP) in patients with hypertension.
  
  
  METHODS
  A cross-sectional analysis of anonymised primary care data was performed for a total of 299,180 adult patients of whom 31,676 (10.6 %) had a diagnosis of hypertension. We compared mean SBP in patients with hypertension alone and those with one or more co-morbidities and analysed the effect of type of comorbidity on SBP. We constructed a regression model to identify the determinants of SBP control.
  
  
  RESULTS
  The strongest predictor of mean SBP was the number of comorbidities, β -0.13 (p < 0.05). Other predictors included Afro-Caribbean ethnicity, β 0.05 (p < 0.05), South Asian ethnicity, β -0.03 (p < 0.05), age, β 0.05 (p < 0.05), male gender, β 0.05 (p < 0.05) and number of hypotensive drugs β 0.06 (p < 0.05). SBP was lower by a mean of 2.03 mmHg (-2.22, -1.85) for each additional comorbidity and was lower in MM regardless of the type of morbidity.
  
  
  CONCLUSIONS
  Hypertensive patients with MM had lower SBP than those with hypertension alone; the greater the number of MM, the lower the SBP. We found no evidence that BP control was related to BP targets, medication category or specific co-morbidity. Further research is needed to determine whether consultation rate, "white-coat hypertension" or medication adherence influence BP control in MM.
authors.affiliation: King's College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London, SE1 3QD, UK. chandra.sarkar@kcl.ac.uk.
authors.forename: Chandra
authors.initials: C
authors.lastname: Sarkar
authors.affiliation: Lambeth-Southwark Public Health Directorate, 160 Tooley Street, London, SE1 2QH, UK. hiten.dodhia@southwark.gov.uk.
authors.forename: Hiten
authors.initials: H
authors.lastname: Dodhia
authors.affiliation: Lambeth-Southwark Public Health Directorate, 160 Tooley Street, London, SE1 2QH, UK. james.crompton@southwark.gov.uk.
authors.forename: James
authors.initials: J
authors.lastname: Crompton
authors.affiliation: King's College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London, SE1 3QD, UK. peter.1.schofield@kcl.ac.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Schofield
authors.affiliation: King's College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London, SE1 3QD, UK. patrick.white@kcl.ac.uk.
authors.forename: Patrick
authors.initials: P
authors.lastname: White
authors.affiliation: Imperial College London, Faculty of Medicine, School of Public Health, South Kensington Campus, London, SW7 2AZ, UK. c.millett@imperial.ac.uk.
authors.forename: Christopher
authors.initials: C
authors.lastname: Millett
authors.affiliation: King's College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London, SE1 3QD, UK. mark.ashworth@kcl.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Ashworth
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001795:Blood Pressure Determination; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D016014:Linear Models; D008131:London / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents