Pneumonia and the incidence of cancer: a Danish nationwide cohort study

Investigating causal associations between pneumonia and lung cancer using a bidirectional mendelian randomization framework

BACKGROUND

Pneumonia and lung cancer are both major respiratory diseases, and observational studies have explored the association between their susceptibility. However, due to the presence of potential confounders and reverse causality, the comprehensive causal relationships between pneumonia and lung cancer require further exploration.

METHODS

Genome-wide association study (GWAS) summary-level data were obtained from the hitherto latest FinnGen database, COVID-19 Host Genetics Initiative resource, and International Lung Cancer Consortium. We implemented a bidirectional Mendelian randomization (MR) framework to evaluate the causal relationships between several specific types of pneumonia and lung cancer. The causal estimates were mainly calculated by inverse-variance weighted (IVW) approach. Additionally, sensitivity analyses were also conducted to validate the robustness of the causalty.

RESULTS

In the MR analyses, overall pneumonia demonstrated a suggestive but modest association with overall lung cancer risk (Odds ratio [OR]: 1.21, 95% confidence interval [CI]: 1.01 - 1.44, P = 0.037). The correlations between specific pneumonia types and overall lung cancer were not as significant, including bacterial pneumonia (OR: 1.07, 95% CI: 0.91 - 1.26, P = 0.386), viral pneumonia (OR: 1.00, 95% CI: 0.95 - 1.06, P = 0.891), asthma-related pneumonia (OR: 1.18, 95% CI: 0.92 - 1.52, P = 0.181), and COVID-19 (OR: 1.01, 95% CI: 0.78 - 1.30, P = 0.952). Reversely, with lung cancer as the exposure, we observed that overall lung cancer had statistically crucial associations with bacterial pneumonia (OR: 1.08, 95% CI: 1.03 - 1.13, P = 0.001) and viral pneumonia (OR: 1.09, 95% CI: 1.01 - 1.19, P = 0.037). Sensitivity analysis also confirmed the robustness of these findings.

CONCLUSION

This study has presented a systematic investigation into the causal relationships between pneumonia and lung cancer subtypes. Further prospective study is warranted to verify these findings.

Risk factors for hospital-acquired pneumonia in hip fracture patients: A systematic review and meta-analysis

BACKGROUND

This study aimed to comprehensively assess the prevalence and risk factors for Hospital-acquired pneumonia (HAP) in hip fracture patients by meta-analysis.

METHODS

Systematically searched 4 English databases and 4 Chinese databases from inception until October 20, 2022. All studies involving risk factors of HAP in patients with hip fractures will be considered. Newcastle-Ottawa Scale was used to evaluate the quality of the included studies. The results were presented through Review Manager 5.4 with the pooled odds ratio (OR) and 95% confidence interval.

RESULTS

Of 35 articles included in this study, the incidence of HAP was 8.9%. 43 risk factors for HAP were initially included, 23 were eventually involved in the meta-analysis, and 21 risk factors were significant. Among them, the 4 most frequently mentioned risk factors were as follows: Advanced age (OR 1.07, 95% CI 1.05-1.10), chronic obstructive pulmonary disease (COPD) (OR 3.44, 95% CI 2.83-4.19), time from injury to operation (OR 1.09, 95% CI 1.07-1.12), time from injury to operation ≥ 48 hours (OR 3.59, 95% CI 2.88-4.48), and hypoalbuminemia < 3.5g/dL (OR 2.68, 95% CI 2.15-3.36).

DISCUSSION

Hip fracture patients diagnosed with COPD have a 3.44 times higher risk of HAP compared to the general hip fracture patients. The risk of HAP also increases with age, with patients over 70 having a 2.34-fold higher risk and those over 80 having a 2.98-fold higher risk. These findings highlight the need for tailored preventive measures and timely interventions in vulnerable patient populations. Additionally, hip fracture patients who wait more than 48 hours for surgery have a 3.59-fold higher incidence of HAP. This emphasizes the importance of swift surgical intervention to minimize HAP risk. However, there are limitations to consider in this study, such as heterogeneity in selected studies, inclusion of only factors identified through multivariate logistic regression, and the focus on non-randomized controlled trial studies.

Risk factors for hospital-acquired pneumonia in hip fracture patients: a systematic review and meta-analysis

OBJECTIVE

This study aimed to systematically assess the incidence and risk factors for hospital-acquired pneumonia (HAP) in hip fracture patients by meta-analysis.

METHODS

Systematically searched four English databases (PubMed, EMBASE, The Cochrane Library, and Web Of Science) and four Chinese databases (CNKI, CQVIP, Sinomed, and WAN FANG) from inception until 20 November 2023. All studies involving risk factors of HAP in patients with hip fractures were considered. Newcastle-Ottawa Scale was used to evaluate the quality of the included studies. The results were presented with the pooled odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

Of 35 articles (337,818 patients) included in this study, the incidence of HAP was 89 per 1000 cases. Twenty-three risk factors were eventually involved in the meta-analysis, and 21 risk factors were significant. Our study has identified four significant risk factors (advanced age, preoperative time, COPD, and hypoalbuminemia) associated with HAP, as follows: Advanced age as a continuous variable (OR 1.07, 95% CI 1.05-1.10), Advanced age > 70 years (OR 2.34, 95% CI 1.77-3.09), Advanced age > 80 years (OR 2.98, 95% CI 2.06-4.31), Chronic obstructive pulmonary disease (COPD) (OR 3.44, 95% CI 2.83-4.19), Time from injury to operation as a continuous variable (OR 1.09, 95% CI 1.07-1.12), Time from injury to operation ≥48 h (OR 3.59, 95% CI 2.88-4.48), Hypoalbuminemia < 3.0 g/dL (OR 3.03, 95% CI 1.93-4.73), and Hypoalbuminemia < 3.5 g/dL (OR 2.68, 95% CI 2.15-3.36). However, it is important to note that all the studies included in our research were retrospective in nature, which introduces certain limitations to the level of evidence and the ability to establish causal inferences.

DISCUSSION

Patients who have suffered hip fractures are at an increased risk of developing postoperative hospital-acquired pneumonia, which can lead to prolonged hospital stays and adverse clinical outcomes. Consequently, the identification of these risk factors offers novel insights and methodologies for healthcare professionals in terms of both prevention and treatment.

TRIAL REGISTRATION

Registration number: INPLASY2022100091.

Brain Abscess and Risk of Cancer: A Nationwide Population-Based Cohort Study

Background and objectives:

Underlying occult cancer could potentially explain some of the observed increased long-term mortality among brain abscess patients.

Methods:

Nationwide, population-based healthcare registries were used to examine long-term risks of cancer in brain abscess patients from 1982 through 2016 compared with a population comparison cohort individually matched (10:1) on age, sex, and residence. Cumulative incidences and adjusted cause-specific hazard rate ratios (HRR) with 95% confidence intervals (CIs) for cancer were computed. Potential confounding by family-related factors was explored by comparing cumulative incidences of cancer among siblings of both groups.

Results:

Among 1,384 brain abscess patients (37% female, median age 50 years, IQR 33-63), cancer was observed in 218 (16%) compared with 1,657/13,838 (12%) in the comparison cohort yielding an adj. HRR of 2.09 (95% CI 1.79-2.45). Median time to diagnosis of cancer was 1.8 years (IQR 0.02-9.1) in brain abscess patients and 8.6 years (IQR 3.9-15.9) in comparison cohort. Among brain abscess patients, central nervous system and eye cancer was diagnosed in 59 (4.3%), of which 47/59 (80%) occurred within 90 days of the admission date, metastasizing cancer in 54 (3.9%), respiratory tract cancer in 48 (3.5%), and gastro-intestinal cancer in 36 (2.6%). Results remained consistent in almost all subgroups and in sensitivity analyses. Accounting for competing risk of death, the 1-, 5-, 10-, and 35-year cumulative incidence of cancer was 7% (95% CI 6-8), 11% (95% CI 9-12), 13% (95% CI 11-15), and 24% (95% CI 20-27) in brain abscess patients compared with 0.7% (95% CI 0.6-0.9), 4% (95% CI 4-5), 8% (95% CI 8-9), and 25% (95% CI 23-27) in the comparison cohort. The cumulative incidences of cancer among siblings of brain abscess patients was 10% and 12% among siblings of the comparison cohort.

Discussion:

Brain abscess was associated with substantially increased risk of cancer during the first ten years after diagnosis.

Incidence of lung cancer following pneumonia in smokers: a population-based study

BACKGROUND

Pneumonia is more common in smokers compared with non-smokers. A high 1-year prevalence of lung cancer following hospitalization for pneumonia was demonstrated in heavy smokers.

AIM

To assess the association between hospitalization for pneumonia among ever-smokers and subsequent lung cancer risk.

DESIGN

Retrospective analysis.

METHODS

The study cohort included all ever-smokers aged 55-80 hospitalized for pneumonia between the years 2010-15 covered by a large medical insurer in Israel. Controls were matched to cases by age in a 4:1 ratio. The primary outcome was the association between hospitalization for pneumonia and subsequent 1-year incidence of lung cancer, adjusted for gender, smoking status (past/current) and pack years. Pre-specified sensitivity analyses excluded heavy smokers (smoking history of more than 30 pack years) and patients diagnosed with lung cancer within 30 days of hospitalization, as they probably had clinical or radiological findings suggestive of lung cancer, making them ineligible for screening.

RESULTS

Lung cancer was identified in 275 of 12 807 (2.1%) patients following hospitalization for pneumonia and in 44 of 51 228 (0.1%) controls (adjusted odds ratio 22.46, 95% CI 16.29-30.96, P < 0.001). Among patients hospitalized for pneumonia, 1-year lung cancer incidence remained high after excluding heavy smokers and patients diagnosed within 30 days of the index date (1.3% and 1.4%, respectively).

CONCLUSIONS

Hospitalization for pneumonia is associated with high 1-year incidence of lung cancer in ever-smokers, supporting the important role of the widely used practice of performing follow up imaging post-pneumonia to exclude occult malignancy.

Association between tramadol use and risk of pneumonia in the middle-aged and elderly populations: a propensity-score matched cohort study

BACKGROUND

Tramadol is a widely used weak opioid; however, the evidence for its safety profile in respiratory system needs additional information. We aimed to examine whether tramadol use is associated with an increased risk of pneumonia in the general population.

METHODS

We conducted five propensity-score (PS) matched cohort studies in The Health Improvement Network database. Participants aged ≥50-years initiated tramadol were compared with those initiated one of the following analgesics: codeine (n=144,506), naproxen (n=113,028), diclofenac (n=74,297), celecoxib (n=42,538), or etoricoxib (n=27,232). The outcome was incident pneumonia.

OUTCOMES

During six-month follow-up, 395 pneumonia (5.6/1000 person-years) occurred in the tramadol group and 414 pneumonia (5.9/1000 person-years) occurred in the PS matched codeine group. Compared with codeine group, the risk of pneumonia was lower in the tramadol group (hazard ratio [HR]=0.63, 95% confidence interval [CI]: 0.49-0.82) during the first 30-day follow-up, but comparable between groups over the entire six-month follow-up (HR=0.95, 95%CI: 0.83-1.09). In addition, the risk of pneumonia was higher in the tramadol group than that in the PS matched naproxen (HR=1.68, 95%CI: 1.37-2.06), diclofenac (HR=1.63, 95%CI: 1.31-2.03), celecoxib (HR=1.64, 95%CI: 1.20-2.24), or etoricoxib (HR=1.61, 95%CI: 1.04-2.49) group.

CONCLUSIONS

The present study indicated that tramadol initiators had a lower risk of incident pneumonia than codeine initiators during the short-time follow-up, but had a comparable pneumonia risk compared to codeine initiators and had a higher risk of pneumonia compared to NSAIDs initiators over the entire six-month follow-up duration. Confirmation of the present findings and determination of the underlying mechanism will require more studies.

COVID-19 follow-up planning: what will we be missing?

Admissions to UK hospitals with novel coronavirus disease (COVID-19) are exponentially increasing, yet the healthcare community has not put much thought into follow-up of these patients who, in many cases, will be discharged early from hospital to ensure ongoing bed availability. There is currently no UK publication or guideline suggesting a criterion for safe discharge or follow-up advice for those testing positive for COVID-19. Severe acute respiratory syndrome (SARS) and viral pneumonia share symptoms and certain radiological findings with COVID-19. In 2003, the World Health Organization (WHO) advised that those with confirmed SARS were to self-isolate for 7 days post-discharge, and to have a chest radiograph and full blood count at day 7 [1], while the British Thoracic Society guidelines for community-acquired pneumonia (CAP) only recommend a chest radiograph at 6 weeks if the patient is still symptomatic or has a risk factor for lung cancer [2]. This therefore raises the question, what should be the optimal follow-up duration and imaging modality for hospital survivors of COVID-19? If no follow-up is deemed necessary, what could we be missing?

There is a real need for a discharge plan for COVID-19 survivors in the UK. Follow-up imaging could help assess the resolution of infection, exclude underlying malignancy and identify post-inflammatory fibrosis.https://bit.ly/2YJ8hyg

Pericarditis as a Marker of Occult Cancer and a Prognostic Factor for Cancer Mortality

BACKGROUND

Pericarditis may be a serious complication of malignancy. Its significance as a first symptom of occult cancer and as a prognostic factor for cancer survival is unknown.

METHODS

Using Danish medical databases, we conducted a nationwide cohort study of all patients with a first-time diagnosis of pericarditis during 1994 to 2013. We excluded patients with previous cancer and followed up the remaining patients for subsequent cancer diagnosis until November 30, 2013. We calculated risks and standardized incidence ratios of cancer for patients with pericarditis compared with the general population. We assessed whether pericarditis predicts cancer survival by the Kaplan-Meier method and Cox regression using a matched comparison cohort of cancer patients without pericarditis.

RESULTS

Among 13 759 patients with acute pericarditis, 1550 subsequently were diagnosed with cancer during follow-up. The overall cancer standardized incidence ratio was 1.5 (95% confidence interval [CI], 1.4-1.5), driven predominantly by increased rates of lung, kidney, and bladder cancer, lymphoma, leukemia, and unspecified metastatic cancer. The <3-month cancer risk among patients with pericarditis was 2.7%, and the standardized incidence ratio was 12.4 (95% CI, 11.2-13.7). The 3- to <12-month standardized incidence ratio of cancer was 1.5 (95% CI, 1.2-1.7), subsequently decreasing to 1.1 (95% CI, 1.0-1.2). Three-month survival after the cancer diagnosis was 80% and 86% among those with and without pericarditis, respectively, and the hazard ratio was 1.5 (95% CI, 1.3-1.8). One-year survival was 65% and 70%, respectively, corresponding to a 3- to <12-month hazard ratio of 1.3 (95% CI, 1.1-1.5).

CONCLUSIONS

Pericarditis may be a marker of occult cancer and augurs increased mortality after a cancer diagnosis.

Methodological choices affect cancer incidence rates: a cohort study

Background

Incidence rates are fundamental to epidemiology, but their magnitude and interpretation depend on methodological choices. We aimed to examine the extent to which the definition of the study population affects cancer incidence rates.

Methods

All primary cancer diagnoses in Sweden between 1958 and 2010 were identified from the national Cancer Register. Age-standardized and age-specific incidence rates of 29 cancer subtypes between 2000 and 2010 were calculated using four definitions of the study population: persons resident in Sweden 1) based on general population statistics; 2) with no previous subtype-specific cancer diagnosis; 3) with no previous cancer diagnosis except non-melanoma skin cancer; and 4) with no previous cancer diagnosis of any type. We calculated absolute and relative differences between methods.

Results

Age-standardized incidence rates calculated using general population statistics ranged from 6% lower (prostate cancer, incidence rate difference: -13.5/100,000 person-years) to 8% higher (breast cancer in women, incidence rate difference: 10.5/100,000 person-years) than incidence rates based on individuals with no previous subtype-specific cancer diagnosis. Age-standardized incidence rates in persons with no previous cancer of any type were up to 10% lower (bladder cancer in women) than rates in those with no previous subtype-specific cancer diagnosis; however, absolute differences were <5/100,000 person-years for all cancer subtypes.

Conclusions

For some cancer subtypes incidence rates vary depending on the definition of the study population. For these subtypes, standardized incidence ratios calculated using general population statistics could be misleading. Moreover, etiological arguments should be used to inform methodological choices during study design.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-017-0120-x) contains supplementary material, which is available to authorized users.

The Gamma Gap and All-Cause Mortality

Background

The difference between total serum protein and albumin, i.e. the gamma gap, is a frequently used clinical screening measure for both latent infection and malignancy. However, there are no studies defining a positive gamma gap. Further, whether it is an independent risk factor of mortality is unknown.

Methods and Findings

This study examined the association between gamma gap, all-cause mortality, and specific causes of death (cardiovascular, cancer, pulmonary, or other) in 12,260 participants of the National Health and Nutrition Examination Survey (NHANES) from 1999–2004. Participants had a comprehensive metabolic panel measured, which was linked with vital status data from the National Death Index. Cause of death was based on ICD10 codes from death certificates. Analyses were performed with Cox proportional hazards models adjusted for mortality risk factors. The mean (SE) age was 46 (0.3) years and the mean gamma gap was 3.0 (0.01) g/dl. The population was 52% women and 10% black. During a median follow-up period of 4.8 years (IQR: 3.3 to 6.2 years), there were 723 deaths. The unadjusted 5-year cumulative incidences across quartiles of the gamma gap (1.7–2.7, 2.8–3.0, 3.1–3.2, and 3.3–7.9 g/dl) were 5.7%, 4.2%, 5.5%, and 7.8%. After adjustment for risk factors, participants with a gamma gap of ≥3.1 g/dl had a 30% higher risk of death compared to participants with a gamma gap <3.1 g/dl (HR: 1.30; 95%CI: 1.08, 1.55; P = 0.006). Gamma gap (per 1.0 g/dl) was most strongly associated with death from pulmonary causes (HR 2.22; 95%CI: 1.19, 4.17; P = 0.01).

Conclusions

The gamma gap is an independent risk factor for all-cause mortality at values as low as 3.1 g/dl (in contrast to the traditional definition of 4.0 g/dl), and is strongly associated with death from pulmonary causes. Future studies should examine the biologic pathways underlying these associations.