title: Community-onset sepsis and its public health burden: a systematic review.
abstract: BACKGROUND
  Sepsis is a life-threatening condition and major contributor to public health and economic burden in the industrialised world. The difficulties in accurate diagnosis lead to great variability in estimates of sepsis incidence. There has been even greater uncertainty regarding the incidence of and risk factors for community-onset sepsis (COS). We systematically reviewed the recent evidence on the incidence and risk factors of COS in high income countries (North America, Australasia, and North/Western Europe).
  
  
  METHODS
  Cohort and case-control studies were eligible for inclusion. Medline and Embase databases were searched from 2002 onwards. References of relevant publications were hand-searched. Two reviewers screened titles/abstracts and full-texts independently. One reviewer extracted data and appraised studies which were cross-checked by independent reviewers. Disagreements were resolved via consensus. Odds ratios (ORs) and 95 percent confidence intervals (95 % CIs) were ascertained by type of sepsis (non-severe, severe, and septic shock).
  
  
  RESULTS
  Ten cohort and 4 case-control studies were included. There was a wide variation in the incidence (# cases per 100,000 per year) of non-severe sepsis (range: 64-514), severe sepsis (range: 40-455), and septic shock (range: 9-31). Heterogeneity precluded statistical pooling. Two cohort and 4 case-control studies reported risk factors for sepsis. In one case-control and one cohort study, older age and diabetes were associated with increased risk of sepsis. The same case-control study showed an excess risk for sepsis in participants with clinical conditions (e.g., immunosuppression, lung disease, and peripheral artery disease). In one cohort study, higher risk of sepsis was associated with being a nursing home resident (OR = 2.60, 95 % CI: 1.20, 5.60) and in the other cohort study with being physically inactive (OR = 1.33, 95 % CI: 1.13, 1.56) and smoking tobacco (OR = 1.85, 95 % CI: 1.54, 2.22). The evidence on sex, ethnicity, statin use, and body mass index as risk factors was inconclusive.
  
  
  CONCLUSIONS
  The lack of a valid standard approach for defining sepsis makes it difficult to determine the true incidence of COS. Differences in case ascertainment contribute to the variation in incidence of COS. The evidence on COS is limited in terms of the number and quality of studies. This review highlights the urgent need for an accurate and standard method for identifying sepsis. Future studies need to improve the methodological shortcomings of previous research in terms of case definition, identification, and surveillance practice.
  
  
  BACKGROUND
  PROSPERO CRD42015023484.
authors.affiliation: Communicable Disease Control Epidemiology and Evidence; Populations, Evidence and Technologies, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK. a.tsertsvadze.1@warwick.ac.uk.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tsertsvadze
authors.affiliation: Communicable Disease Control Epidemiology and Evidence; Populations, Evidence and Technologies, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Pam
authors.initials: P
authors.lastname: Royle
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Farah
authors.initials: F
authors.lastname: Seedat
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cooper
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Crosby
authors.affiliation: Communicable Disease Control Epidemiology and Evidence; Populations, Evidence and Technologies, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.|NIHR Health Protections Research Unit in Gastrointestinal Infections, University of Oxford, Oxford, UK.
authors.forename: Noel
authors.initials: N
authors.lastname: McCarthy
mesh_terms: D000367:Age Factors; D044362:Australasia / Q000453:epidemiology; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000453:epidemiology*; D005060:Europe / Q000453:epidemiology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D016867:Immunocompromised Host; D008171:Lung Diseases / Q000453:epidemiology; D009656:North America / Q000453:epidemiology; D009735:Nursing Homes; D016017:Odds Ratio; D058729:Peripheral Arterial Disease / Q000453:epidemiology; D011634:Public Health; D012111:Residence Characteristics; D012307:Risk Factors; D057185:Sedentary Behavior; D018805:Sepsis / Q000453:epidemiology*; D012737:Sex Factors; D012772:Shock, Septic / Q000453:epidemiology; D012907:Smoking / Q000453:epidemiology*
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors
keywords: Community-onset sepsis; Incidence of sepsis or severe sepsis; Risk factors