Chronic Statin Use and Long-Term Rates of Sepsis: A Population-Based Cohort Study

Mediating Effects of Frailty Indicators on the Risk of Sepsis After Cancer

BACKGROUND

Cancer survivors are at increased risk of sepsis, possibly attributed to weakened physiologic conditions. The aims of this study were to examine the mediation effect of indicators of frailty on the association between cancer survivorship and sepsis incidence and whether these differences varied by race.

METHODS

We performed a prospective analysis using data from the REasons for Geographic and Racial Differences in Stroke cohort from years 2003 to 2012. We categorized frailty as the presence of ≥2 frailty components (weakness, exhaustion, and low physical activity). We categorized participants as "cancer survivors" or "no cancer history" derived from self-reported responses of being diagnosed with any cancer. We examined the mediation effect of frailty on the association between cancer survivorship and sepsis incidence using Cox regression. We repeated analysis stratified by race.

RESULTS

Among 28 062 eligible participants, 2773 (9.88%) were cancer survivors and 25 289 (90.03%) were no cancer history participants. Among a total 1315 sepsis cases, cancer survivors were more likely to develop sepsis (12.66% vs 3.81%, P < .01) when compared to participants with no cancer history (hazard ratios: 2.62, 95% confidence interval: 2.31-2.98, P < .01). The mediation effects of frailty on the log-hazard scale were very small: weakness (0.57%), exhaustion (0.31%), low physical activity (0.20%), frailty (0.75%), and total number of frailty indicators (0.69%). Similar results were observed when stratified by race.

CONCLUSION

Cancer survivors had more than a 2-fold increased risk of sepsis, and indicators of frailty contributed to less than 1% of this disparity.

Association of baseline steroid use with long-term rates of infection and sepsis in the REGARDS cohort

BACKGROUND

Prior studies associate steroid use with infection risk but were limited to select populations and short follow-up periods. The association of steroid use with long-term risk of community-acquired infections is unknown. We sought to determine the association of steroid risk with long-term risks of community- acquired infections and sepsis.

METHODS

We used data on 30,239 adults aged ≥ 45 years old from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. The primary exposure was oral or injectable steroid use, determined from medication inventory obtained at baseline in-home visit. The primary outcome was time to first infection event during 2003-2012, determined through adjudicated review of hospital records. We determined associations between baseline steroid use and first infection hospitalization events using Cox proportional hazards models, adjusting for demographics, health behaviors, chronic medical conditions, and medication adherence. Among the first infection hospitalization events, we also determined the association between baseline steroid use and sepsis.

RESULTS

Steroid use was reported in 2.24% (n = 677) of the study population. There were 2593 incident infection events during the 10-year follow-up period. Infection incidence rates were higher for steroid than non-steroid users (37.99 vs. 13.79 per 1000 person-years). Steroid use was independently associated with increased risk of infection (adjusted HR 2.10, 95% CI: 1.73-2.56). Among first-infection events, steroid use was associated with increased odds of sepsis (adjusted OR 2.11, 95% CI: 1.33-3.36). The associations persisted in propensity matched analyses as well as models stratified by propensity score and medication adherence.

CONCLUSIONS

In this population-based cohort study, baseline steroid use was associated with increased long-term risks of community-acquired infections and sepsis.

Cholesterol levels and long-term rates of community-acquired sepsis

Background

Dyslipidemia is a risk factor for cardiovascular disease, with elevated low-density lipoprotein cholesterol (LDL-C) and decreased high-density lipoprotein cholesterol (HDL-C) recognized as risk factors for acute coronary events. Studies suggest an association between low cholesterol levels and poor outcomes in acute sepsis. We sought to determine the relationship between baseline cholesterol levels and long-term rates of sepsis.

Methods

We used data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort, a population-based cohort of 30,239 community-dwelling adults. The primary outcome was first sepsis event, defined as hospitalization for an infection with the presence of ≥2 systemic inflammatory response syndrome criteria (abnormal temperature, heart rate, respiratory rate, white blood cell count) during the first 28 hours of hospitalization. Cox models assessed the association between quartiles of HDL-C or LDL-C and first sepsis event, adjusted for participant demographics, health behaviors, chronic medical conditions, and biomarkers.

Results

We included 29,690 subjects with available baseline HDL-C and LDL-C. There were 3423 hospitalizations for serious infections, with 1845 total sepsis events among 1526 individuals. Serum HDL-C quartile was not associated with long-term rates of sepsis (hazard ratio (HR) (95% CI): Q1 (HDL-C 5–40 mg/dl), 1.08 (0.91–1.28); Q2 (HDL-C 41–49 mg/dl), 1.06 (0.90–1.26); Q3 (HDL-C 50–61 mg/dl), 1.04 (0.89–1.23); Q4, reference). However, compared with the highest quartile of LDL-C, low LDL-C was associated with higher rates of sepsis (Q1 (LDL-C 3–89 mg/dl), 1.30 (1.10–1.52); Q2 (LDL-C 90–111 mg/dl), 1.24 (1.06–1.47); Q3 (LDL-C 112–135 mg/dl), 1.07 (0.91–1.26); Q4, reference).

Conclusion

Low LDL-C was associated with higher long-terms rates of community-acquired sepsis. HDL-C level was not associated with long-term sepsis rates.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1579-8) contains supplementary material, which is available to authorized users.

Community-onset sepsis and its public health burden: a systematic review

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.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015023484.

Systematic review of the in vitro effects of statins on oral and perioral microorganisms

Statins are medications administered orally and are widely used for lowering the blood cholesterol level. The aim of this study was to investigate the effects of orally administered statins on microorganisms infecting oral and perioral tissues. We performed a systematic review of published studies of the in vitro antimicrobial effects of statins on bacteria, viruses, and fungi, and searched PubMed, Web of Science, Cochrane Central, and Google scholar. Studies show that most statins exhibit antimicrobial effects against various oral microorganisms. Simvastatin is most effective against the periodontal pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, and against most dental plaque bacteria, including Streptococcus mutans. Statins also exhibit antiviral properties against human cytomegalovirus, hepatitis B virus, and hepatitis C virus, and have antifungal properties against Candida albicans, Aspergillus fumigatus, and Zygomycetes spp. There were notable differences in the minimum inhibitory concentrations (MICs) between different studies, which may be attributed to differences in study design. Further studies are warranted to ascertain if statins can be solubilized so that patients, who have been prescribed statins for cardiovascular diseases, can use the medication as a swish and swallow, giving patients the added benefit of the antimicrobial action topically in the mouth against infectious oral diseases.

Effects of simvastatin on the expression of inducible NOS in acute lung injury in septic rats

BACKGROUND

The available evidence suggests that simvastatin plays a beneficial role in lung injury. In addition, statins have been shown to inhibit the activity of inducible nitric oxide synthase (iNOS). The aim of the present study was to investigate the effects of simvastatin on iNOS expression based on a lipopolysaccharide (LPS)-induced septic rat model.

METHODS

Thirty-six rats were randomly divided into 3 groups (control group, sepsis group and simvastatin group). A rat model of sepsis was established with LPS. The simvastatin group was pre-treated with simvastatin, whereas the control and sepsis groups were treated with saline before LPS treatment. LPS was injected into the rats in the simvastatin and sepsis groups, while as a negative control, the control group received saline alone. The oxygenation index, expression levels of iNOS and IL-6, and pathological integral of lung injury were analyzed to evaluate the effect of simvastatin on septic rats.

RESULTS

Compared with the septic group, significant decreases in the oxygenation index and expression level of iNOS were observed in the simvastatin group. Furthermore, simvastatin treatment resulted in a significant decrease in iNOS levels and the pathological integral of lung injury score in septic rats.

CONCLUSION

Simvastatin can relieve acute lung injury induced by sepsis in rats. Decreasing iNOS levels may contribute to the protective role of simvastatin in lung injury.