Risk of Non-Vertebral Fracture in Gout Compared to Rheumatoid Arthritis

Objective: To evaluate the risk of non-vertebral fractures in patients with gout compared with those with rheumatoid arthritis (RA). Methods: Using claims data from Medicare (2008–2015), we conducted a cohort study of patients with gout versus RA matched on age, sex, and index date with a 1:1 ratio. The primary outcome was a composite endpoint of non-vertebral fractures including hip, pelvis, humerus, and wrist identified with the validated algorithms. We also assessed hip fractures separately. Multivariable Cox proportional hazards regression estimated the hazard ratio (HR) for the outcomes in gout versus RA adjusted for 45 covariates. Results: We included a total of 134,157 matched pairs of gout and RA patients (mean age: 73.7 years). Risk factors for fracture were more prevalent in RA, while other comorbidities including obesity, coronary heart disease, hypertension, and diabetes were more common in gout. Over the mean 2.8 years follow-up, the incidence rate (IR)/1000 person-year (PY) of non-vertebral fractures was 10.42 in gout and 15.01 in RA. For hip fractures, the IR/1000 PY was 4.86 in gout and 7.73 in RA. The multivariable HR associated with gout versus RA was 0.84 (95% confidence interval (CI) 0.80–0.88) for non-vertebral fractures and 0.76 (95% CI 0.71–0.82) for hip fractures. Stratified analyses by age, sex, prior fractures, steroid use, and TNF inhibitor use showed similar results. Conclusions: In this large cohort of older patients, gout was associated with a modestly decreased risk of non-vertebral or hip fractures versus RA. However, non-vertebral fractures occurred frequently in both gout and RA.

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Use of Tramadol or Other Analgesics in Patients Treated in the Emergency Department as a Risk Factor for Opioid Use

Pain Research and Management ◽

10.1155/2020/8847777 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Jorge Enrique Machado-Alba ◽

Laura Sofía Serna-Echeverri ◽

Luis Fernando Valladales-Restrepo ◽

Manuel Enrique Machado-Duque ◽

Andrés Gaviria-Mendoza

Keyword(s):

Emergency Departments ◽

Proportional Hazards ◽

Cox Proportional Hazards ◽

Opioid Use ◽

Proportional Hazards Regression ◽

The Mean ◽

One Year ◽

The One ◽

First Time

The objective of this cohort study was to determine the association between the use of tramadol in emergency departments and the later consumption of opioids at the outpatient level in a group of patients from Colombia. Based on a medication dispensation database, patients over 18 years of age treated in different clinics in Colombia who for the first time received tramadol, dipyrone, or a nonsteroidal anti-inflammatory drug (NSAID) in the emergency room between January and December 2018 were identified. Three mutually exclusive cohorts were created, and each patient was followed up for 12 months after the administration of the analgesic to identify new formulations of any opioid. A Cox proportional-hazards regression model was constructed to identify variables associated with receiving a new opioid. A total of 12,783 patients were identified: 6020 treated with dipyrone, 5309 treated with NSAIDs, and 1454 treated with tramadol. The mean age was 47.1 ± 20.4 years, and 61.6% were women. A total of 17.3% (n = 2207) of all patients received an opioid during follow-up. Those treated with tramadol received a new opioid with a higher frequency (n = 346, 23.8%) than the other cohorts (14.7% NSAIDs and 17.9% dipyrone, both p < 0.001 ). In the tramadol group, using more than 10 mg of morphine equivalents was associated with a greater use of new opioids (HR:1.47, 95%CI:1.12–1.93). Patients treated with tramadol in emergency departments have a higher risk of opioid use at the one-year follow-up than those treated with NSAIDs or dipyrone.

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Real-world study of cetuximab used every other week versus weekly in US patients with metastatic colorectal cancer (mCRC).

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.15_suppl.e15087 ◽

2019 ◽

Vol 37 (15_suppl) ◽

pp. e15087-e15087 ◽

Cited By ~ 1

Author(s):

Francois-Xavier Lamy ◽

Michael Batech ◽

Shaista Salim ◽

Emmanuelle Boutmy ◽

Chris Pescott ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Proportional Hazards ◽

Cox Model ◽

Cox Proportional Hazards ◽

Patient Death ◽

Claims Database ◽

Proportional Hazards Regression ◽

The Mean

e15087 Background: After an initial dose of 400 mg/m², cetuximab (CET) at a dose of 250 mg/m² in combination with chemotherapy (CT) is approved for once-weekly (q1w) use in the treatment of RAS wild-type metastatic colorectal cancer (mCRC). However, off-label use of CET 500 mg/m2 administered every other week (q2w) has been observed in clinical practice. This study aimed to test the noninferiority of q2w vs q1w administration on overall survival (OS) using US claims data. Methods: Using IBM MarketScan, a large US insurance claims database, a cohort of patients with mCRC treated with CET + CT between 2010 and 2016 was identified and classified as q1w or q2w based on observed infusion patterns. The initial CET prescription was defined as the index date, and patient death was determined using a previously published algorithm. Confounding was accounted for using high-dimensional propensity scoring (hdPS) methodology with inverse probability of treatment weighting (IPTW). OS for both groups was compared using Cox proportional hazards regression. Confounders that remained imbalanced after hdPS with IPTW were added to the Cox model. The noninferiority of the q2w regimen was tested with a margin hazard ratio (HR) of 1.25 for q2w vs q1w. Results: 2,869 patients with mCRC exposed to CET were identified of which 1,865 (65.0%) and 1,004 (35.0%) were classified in the q1w and q2w groups, respectively. The mean age of patients was 60.1±11.7 years for q1w and 58.1±11.1 years for q2w. Most patients were male: 57.5% and 60.8% in q1w and q2w, respectively. Approximately 70% of patients in both groups had received prior treatment for mCRC. The most frequently used CT with CET was irinotecan based (64.5% in q1w and 76.5% in q2w). There were 1,628 deaths observed during follow-up (56.7%). After hdPS with IPTW adjustment, differences remained in associated CT (standardized difference <0.25). Crude HR for OS was 1.05 (95% CI, 0.94-1.18), and adjusted HR for OS was 1.04 (95% CI, 0.93-1.17). The inferiority hypothesis was rejected at p<0.001. Conclusions: In this large US claims database, when assessing OS, the q2w administration schedule was found to be noninferior to the q1w schedule in patients with mCRC.

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Sex-Specific Associations between Blood Pressure and Risk of Atrial Fibrillation Subtypes in the Tromsø Study

Journal of Clinical Medicine ◽

10.3390/jcm10071514 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1514

Author(s):

Hilde Espnes ◽

Jocasta Ball ◽

Maja-Lisa Løchen ◽

Tom Wilsgaard ◽

Inger Njølstad ◽

...

Keyword(s):

Atrial Fibrillation ◽

Blood Pressure ◽

Proportional Hazards ◽

Cox Proportional Hazards ◽

Pressure Management ◽

Reference Models ◽

Proportional Hazards Regression ◽

Hazard Ratios ◽

Increased Risk

The aim of this study was to explore sex-specific associations between systolic blood pressure (SBP), hypertension, and the risk of incident atrial fibrillation (AF) subtypes, including paroxysmal, persistent, and permanent AF, in a general population. A total of 13,137 women and 11,667 men who participated in the fourth survey of the Tromsø Study (1994–1995) were followed up for incident AF until the end of 2016. Cox proportional hazards regression analysis was conducted using fractional polynomials for SBP to provide sex- and AF-subtype-specific hazard ratios (HRs) for SBP. An SBP of 120 mmHg was used as the reference. Models were adjusted for other cardiovascular risk factors. Over a mean follow-up of 17.6 ± 6.6 years, incident AF occurred in 914 (7.0%) women (501 with paroxysmal/persistent AF and 413 with permanent AF) and 1104 (9.5%) men (606 with paroxysmal/persistent AF and 498 with permanent AF). In women, an SBP of 180 mmHg was associated with an HR of 2.10 (95% confidence interval [CI] 1.60–2.76) for paroxysmal/persistent AF and an HR of 1.80 (95% CI 1.33–2.44) for permanent AF. In men, an SBP of 180 mmHg was associated with an HR of 1.90 (95% CI 1.46–2.46) for paroxysmal/persistent AF, while there was no association with the risk of permanent AF. In conclusion, increasing SBP was associated with an increased risk of both paroxysmal/persistent AF and permanent AF in women, but only paroxysmal/persistent AF in men. Our findings highlight the importance of sex-specific risk stratification and optimizing blood pressure management for the prevention of AF subtypes in clinical practice.

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Replacement of potatoes with other vegetables and risk of myocardial infarction in the Danish Diet, Cancer and Health cohort

British Journal Of Nutrition ◽

10.1017/s0007114521000349 ◽

2021 ◽

pp. 1-21

Author(s):

Anne Mette L. Würtz ◽

Mette D. Hansen ◽

Anne Tjønneland ◽

Eric B. Rimm ◽

Erik B. Schmidt ◽

...

Keyword(s):

Myocardial Infarction ◽

Similar Pattern ◽

Proportional Hazards ◽

Cox Proportional Hazards ◽

Heterogeneous Group ◽

Dietary Guidelines ◽

Cox Proportional Hazards Regression ◽

Proportional Hazards Regression ◽

Root Vegetables

ABSTRACT Intake of vegetables is recommended for the prevention of myocardial infarction (MI). However, vegetables make up a heterogeneous group, and subgroups of vegetables may be differentially associated with MI. The aim of this study was to examine replacement of potatoes with other vegetables or subgroups of other vegetables and the risk of MI. Substitutions between subgroups of other vegetables and risk of MI were also investigated. We followed 29,142 women and 26,029 men aged 50-64 years in the Danish Diet, Cancer and Health cohort. Diet was assessed at baseline by using a detailed validated FFQ. Hazards ratios (HR) with 95% CI for the incidence of MI were calculated using Cox proportional hazards regression. During 13.6 years of follow-up, 656 female and 1,694 male cases were identified. Among women, the adjusted HR for MI was 1.02 (95% CI: 0.93, 1.13) per 500 g/week replacement of potatoes with other vegetables. For vegetable subgroups, the HR was 0.93 (95% CI: 0.77, 1.13) for replacement of potatoes with fruiting vegetables and 0.91 (95% CI: 0.77, 1.07) for replacement of potatoes with other root vegetables. A higher intake of cabbage replacing other vegetable subgroups was associated with a statistically non-significant higher risk of MI. A similar pattern of associations was found when intake was expressed in kcal/week. Among men, the pattern of associations was overall found to be similar to that for women. This study supports food-based dietary guidelines recommending to consume a variety of vegetables from all subgroups.

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Consumption of flavonoid-rich fruits, flavonoids from fruits, and stroke risk: a prospective cohort study

British Journal Of Nutrition ◽

10.1017/s0007114521000404 ◽

2021 ◽

pp. 1-26

Author(s):

Qi Gao ◽

Jia-Yi Dong ◽

Renzhe Cui ◽

Isao Muraki ◽

Kazumasa Yamagishi ◽

...

Keyword(s):

Lower Risk ◽

Stroke Risk ◽

Proportional Hazards ◽

Cox Proportional Hazards ◽

Dietary Factors ◽

Citrus Fruits ◽

Proportional Hazards Regression ◽

Hazard Ratios ◽

Index Study

Abstract We sought to examine the prospective associations of specific fruit consumption, in particular flavonoid-rich fruit (FRF) consumption, with the risk of stroke and subtypes of stroke in a Japanese population. A study followed a total of 39,843 men and 47,334 women aged 44-76 years, and free of cardiovascular disease, diabetes, and cancer at baseline since 1995 and 1998 to the end of 2009 and 2012, respectively. Data on total and specific FRF consumption for each participant were obtained using a self-administrated food frequency questionnaire. The hazard ratios (HRs) of stroke in relation to total and specific FRF consumption were estimated through Cox proportional hazards regression models. During a median follow-up of 13.1 years, 4092 incident stroke cases (2557 cerebral infarctions and 1516 hemorrhagic strokes) were documented. After adjustment for age, body mass index, study area, lifestyles, dietary factors, and other risk factors, it was found that total FRF consumption was associated with a significantly lower risk of stroke in women (HR= 0.70; 95% CI, 0.58-0.84), while the association in men was not significant (HR= 0.93; 95% CI, 0.79-1.09). As for specific FRFs, consumptions of citrus fruits, strawberries, and grapes were found associated with a lower stroke risk in women. Higher consumptions of FRFs, in particular citrus fruits, strawberries, and grapes, were associated with a lower risk of developing stroke in Japanese women.

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Development and Validation of a Prognostic Nomogram Model for Recurrence of Non-Muscle Invasive Bladder Cancer

10.21203/rs.3.rs-691739/v1 ◽

2021 ◽

Author(s):

Sanhe Liu ◽

Yongzhi Li ◽

Diansheng Cui ◽

Yuexia Jiao ◽

Liqun Duan ◽

...

Keyword(s):

Bladder Cancer ◽

Risk Stratification ◽

Proportional Hazards ◽

Cox Proportional Hazards ◽

Muscle Invasive Bladder Cancer ◽

Clinicopathologic Characteristics ◽

Cox Proportional Hazards Regression ◽

Proportional Hazards Regression ◽

Muscle Invasive

Abstract BackgroundDifferent recurrence probability of non-muscle invasive bladder cancer (NMIBC) requests different adjuvant treatments and follow-up strategies. However, there is no simple, intuitive, and generally accepted clinical recurrence predictive model available for NMIBC. This study aims to construct a predictive model for the recurrence of NMIBC based on demographics and clinicopathologic characteristics from two independent centers. MethodsDemographics and clinicopathologic characteristics of 511 patients with NMIBC were retrospectively collected. Recurrence free survival (RFS) was estimated using the Kaplan-Meier method and log-rank tests. Univariate Cox proportional hazards regression analysis was used to screen variables associated with RFS, and a multivariate Cox proportional hazards regression model with a stepwise procedure was used to identify those factors of significance. A final nomogram model was built using the multivariable Cox method. The performance of the nomogram model was evaluated with respect to its calibration, discrimination, and clinical usefulness. Internal validation was assessed with bootstrap resampling. X-tile software was used for risk stratification calculated by the nomogram model. ResultsIndependent prognostic factors including tumor stage, recurrence status, and European Association of Urology (EAU) risk stratification group were introduced to the nomogram model. The model showed acceptable calibration and discrimination (area under the receiver operating characteristic [ROC] curve was 0.85; the consistency index [C-index] was 0.79 [95% CI: 0.76 to 0.82]), which was superior to the EAU risk stratification group alone. The decision curve also proved well clinical usefulness. Moreover, all populations could be stratified into three distinct risk groups by the nomogram model. ConclusionsWe established and validated a novel nomogram model that can provide individual prediction of RFS for patients with NMIBC. This intuitively prognostic nomogram model may help clinicians in postoperative treatment and follow-up decision-making.

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The association between lymphopenia and serious infection risk in rheumatoid arthritis

Rheumatology ◽

10.1093/rheumatology/kez349 ◽

2019 ◽

Vol 59 (4) ◽

pp. 762-766

Author(s):

Sujith Subesinghe ◽

Alexander Kleymann ◽

Andrew Ian Rutherford ◽

Katie Bechman ◽

Sam Norton ◽

...

Keyword(s):

Proportional Hazards ◽

Cox Proportional Hazards ◽

Mixed Effect ◽

Proportional Hazards Regression ◽

Effect Model ◽

Serious Infection ◽

Patients At Risk ◽

Using Data ◽

The Relationship

Abstract Objectives To investigate the relationship between occurrence of serious infection (SI) and lymphocyte counts in patients with RA using data from a single centre. Methods We used routinely captured data from a single tertiary rheumatology centre to explore the relationship between lymphopenia and SI risk. Adult RA patients were included over a 5-year follow-up period. Admissions due to confirmed SI were considered. SI rate with 95% confidence intervals was calculated. The association between SI with baseline lymphocyte counts, time-averaged lymphocyte counts throughout all follow-up, and a nadir lymphocyte count was assessed using Cox proportional hazards regression. The relationship between lymphopenia over time and SI was analysed using a mixed-effect model of lymphocyte counts prior to SI. Results This analysis included 1095 patients with 205 SIs during 2016 person-years of follow-up. The SI rate was 4.61/100 patient-years (95% CI: 3.76, 5.65). Compared with patients with nadir lymphocyte counts >1.5 × 109 cells/l, nadir lymphopenia <1 × 109 cells/l was significantly associated with higher SI risk (HR 3.28; 95% CI: 1.59, 6.76), increasing to HR 8.08 (95% CI: 3.74, 17.44) in patients with lymphopenia <0.5 × 109 cells/l. Lymphocyte counts were observed to be reduced in the 30-day period prior to SI. Conclusion Lymphocyte counts below <1.0 × 109 cells/l were associated with higher SI risk in RA patients; the strongest association between lymphopenia and SI was observed when lymphocyte counts were below <0.5 × 109 cells/l. Lymphopenia may be used as a measure to stratify patients at risk of SI.

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Natriuretic Peptide Levels Correlate with Pulmonary Pressures and Prospective Mortality in SCD: Use of This Biomarker To Identify Prevalence and Mortality of Pulmonary Hypertension in the MSH Cohort.

Blood ◽

10.1182/blood.v106.11.1.1 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1-1

Author(s):

Roberto Machado ◽

Martin Steinberg ◽

Duane Bonds ◽

Samir Ballas ◽

William Blackwelder ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Sickle Cell Disease ◽

Sickle Cell ◽

Proportional Hazards ◽

Cox Proportional Hazards ◽

Cell Disease ◽

Risk Of Death ◽

Cox Proportional Hazards Regression ◽

Proportional Hazards Regression

Abstract Pulmonary hypertension [PH-tricuspid regurgitant jet velocity (TRV) ≥2.5 m/s] is a common complication of sickle cell disease associated with high mortality. Identification of biomarkers of PH and mortality could facilitate screening and risk stratification in this population. Validated biomarkers would provide methods for retrospective evaluation of the prevalence and prognosis of PH in large historical cohorts of patients such as the Multicenter Study of Hydroxyurea in Sickle Cell Anemia(MSH). Because brain natriuretic peptide(BNP) is released from the ventricles during pressure strain, we hypothesized that BNP levels would correlate with the severity of PH and prospective risk of death in patients with SCD. BNP was measured in 45 African-American control subjects and 230 patients with SCD. Median (interquartile range) BNP(pg/ml) was higher in patients with PH than patients without PH or controls[+PH: 206(81–701),-PH: 47(26–104), C: 29, P<0.001]. BNP levels directly correlated with age (R=0.32, P<0.001), creatinine (R=0.22, P<0.001), LDH(R=0.31, P<0.001), TRV (R=0.5, P<0.001), pulmonary vascular resistance (R=0.5, P=0.001); and inversely with hemoglobin(R=0.41, P<0.001), cardiac output(R=0.47, P= 0.003) and 6-minute walk distance(R=0.51, P=0.001). The area under the ROC for BNP and the diagnosis of pulmonary hypertension was 0.84 (P<0.001). A cutoff value of 160 pg/ml (corresponding to the 75th percentile for the population) had 58% sensitivity and 98% specificity for the diagnosis of PH. Cox proportional hazards regression identified BNP as an independent predictor of mortality(RR 2.17,95% CI 1.2–3.8, P =0.001) with clear mortality break point at the 75th percentile(160 pg/ml). To independently explore the prevalence and associated risk of PH in patients with sickle cell disease, a BNP value of 160 pg/ml was used as an indicator of PH. BNP levels were then measured in plasma samples collected in 121 patients who were enrolled in the MSH patient’s follow-up study that started in 1996. These patients had received hydroxyurea or placebo for two years, had moderately severe disease based on study entry criteria, and had 9-years of comprehensive follow-up. An abnormal BNP level ≥160 pg/ml was present in 30% of patients in the MSH cohort. BNP levels correlated directly with age(R=0.35, P<0.001) and creatinine (R=0.24, P<0.001), and inversely with hemoglobin(R=−0.54, P<0.001). There was no correlation between BNP and rate of painful episodes or acute chest syndrome, use of hydroxyurea or leukocyte count. A high BNP level in the MSH cohort was associated with mortality by logistic regression(OR 3.04,95% CI 1.2–7.6, P = 0.018) and Cox proportional hazards regression analysis(RR 2.87, P=0.017). The relationship remained significant for continuous log- transformed BNP values and after adjustment for other covariates. These studies confirm that PH is common, mechanistically linked to hemolytic anemia and the major risk factor for death in SCD. Provocatively, the MSH analysis suggests that rates of pain episodes in this small sample of seriously ill patients were unrelated to risk of death: this risk was largely determined by a high BNP level, which is probably explained by undiagnosed hemolysis-associated PH.

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γ-H2AX as a novel prognostic marker in patients with non-small lung cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.e17553 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. e17553-e17553

Author(s):

Dimitrios Matthaios ◽

Panagiotis Hountis ◽

Grigorios Trypsianis ◽

Athanasios Zissimopoulos ◽

Demosthenes Bouros ◽

...

Keyword(s):

Lung Cancer ◽

Overall Survival ◽

Regression Analysis ◽

Proportional Hazards ◽

Prognostic Indicator ◽

Cox Proportional Hazards ◽

Independent Effect ◽

Cox Proportional Hazards Regression ◽

Proportional Hazards Regression

e17553 Background: Phosphorylation of the H2AX histone is an early indicator of DNA double-strand breaks and of the resulting DNA damage response. In the present study we assessed the expression of γ-Η2ΑΧ in a cohort of 96 patients with non-small cell lung carcinoma and evaluated its role as a prognostic indicator in resectable NCSLC patients. Methods: 96 parafin-embedded specimens of non-small lung cancer patients were examined. All patients underwent radical thoracic surgery of primary tumor (lobectomy or pneumonectomy) and regional lymph nodes dissection. γ-Η2ΑΧ expression was assessed by standard immunohistochemistry.Multivariate Cox proportional hazards regression analysis, using a backward selection approach, were performed to explore the independent effect of variables on survival. All tests were two tailed and statistical significance was considered for p values <0.05. Results: Follow-up was available for all patients; mean duration of follow-up was 27.50 ± 14.07 months (range 0.2-57 months, median 24 months). Sixty-three patients (65.2%) died during the follow-up period. The mean survival time was 32.2 ± 1.9 months (95% CI = 28.5 to 35.8 months; median 30.0 months); one, two and three-year survival rates were 86.5 ± 3.5%, 57.3 ± 5.1% and 37.1 ± 5.4% respectively. Low γ-H2AX expression was associated with a significant better survival as compared with those having high γ-H2AX expression (23.2 months for high γ-Η2ΑΧ expressin vs 35.3 months for low γ-H2AX expression, p=0.009; HR=1.95, 95% CI=1.15-3.30). Further investigation with multivariate Cox proportional hazards regression analysis revealed that high expression of γ-H2AX remained independent prognostic factors of worse overall survival (HR=2.15, 95% CI=1.22-3.79, p=0.026). Conclusions: Our study is the first study to demonstrate that overexpression of γ-Η2ΑΧ is an independent prognostic indicator of worse overall survival in patients with non-small lung cancer. Further studies are needed to confirm our results.

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Population-based cohort study examining the association between splenectomy and empyema in adults in Taiwan

BMJ Open ◽

10.1136/bmjopen-2016-015101 ◽

2017 ◽

Vol 7 (9) ◽

pp. e015101 ◽

Cited By ~ 12

Author(s):

Hsien-Feng Lin ◽

Kuan-Fu Liao ◽

Ching-Mei Chang ◽

Cheng-Li Lin ◽

Shih-Wei Lai

Keyword(s):

Cohort Study ◽

Incidence Rate ◽

Proportional Hazards ◽

Population Based ◽

Cox Proportional Hazards ◽

Proportional Hazards Regression ◽

Kaplan Meier ◽

Confounding Variables ◽

Taiwan National Health Insurance

ObjectiveThis study aimed to investigate the association between splenectomy and empyema in Taiwan.MethodsA population-based cohort study was conducted using the hospitalisation dataset of the Taiwan National Health Insurance Program. A total of 13 193 subjects aged 20–84 years who were newly diagnosed with splenectomy from 2000 to 2010 were enrolled in the splenectomy group and 52 464 randomly selected subjects without splenectomy were enrolled in the non-splenectomy group. Both groups were matched by sex, age, comorbidities and the index year of undergoing splenectomy. The incidence of empyema at the end of 2011 was calculated. A multivariable Cox proportional hazards regression model was used to estimate the HR with 95% CI of empyema associated with splenectomy and other comorbidities.ResultsThe overall incidence rate of empyema was 2.56-fold higher in the splenectomy group than in the non-splenectomy group (8.85 vs 3.46 per 1000 person-years). The Kaplan-Meier analysis revealed a higher cumulative incidence of empyema in the splenectomy group than in the non-splenectomy group (6.99% vs 3.37% at the end of follow-up). After adjusting for confounding variables, the adjusted HR of empyema was 2.89 for the splenectomy group compared with that for the non-splenectomy group. Further analysis revealed that HR of empyema was 4.52 for subjects with splenectomy alone.ConclusionThe incidence rate ratio between the splenectomy and non-splenectomy groups reduced from 2.87 in the first 5 years of follow-up to 1.73 in the period following the 5 years. Future studies are required to confirm whether a longer follow-up period would further reduce this average ratio. For the splenectomy group, the overall HR of developing empyema was 2.89 after adjusting for age, sex and comorbidities, which was identified from previous literature. The risk of empyema following splenectomy remains high despite the absence of these comorbidities.

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