A nationwide cohort study of the risk of chronic obstructive pulmonary disease in coeliac disease

Unsupervised representation learning on high-dimensional clinical data improves genomic discovery and prediction

Although high-dimensional clinical data (HDCD) are increasingly available in biobank-scale datasets, their use for genetic discovery remains challenging. Here we introduce an unsupervised deep learning model, Representation Learning for Genetic Discovery on Low-Dimensional Embeddings (REGLE), for discovering associations between genetic variants and HDCD. REGLE leverages variational autoencoders to compute nonlinear disentangled embeddings of HDCD, which become the inputs to genome-wide association studies (GWAS). REGLE can uncover features not captured by existing expert-defined features and enables the creation of accurate disease-specific polygenic risk scores (PRSs) in datasets with very few labeled data. We apply REGLE to perform GWAS on respiratory and circulatory HDCD-spirograms measuring lung function and photoplethysmograms measuring blood volume changes. REGLE replicates known loci while identifying others not previously detected. REGLE are predictive of overall survival, and PRSs constructed from REGLE loci improve disease prediction across multiple biobanks. Overall, REGLE contain clinically relevant information beyond that captured by existing expert-defined features, leading to improved genetic discovery and disease prediction.

Eosinophilic esophagitis and risk of incident major adverse cardiovascular events: a nationwide matched cohort study

BACKGROUND

Inflammatory diseases have been associated with an increased cardiovascular risk. However, data on incident major adverse cardiovascular events (MACE) from large population-based cohorts of patients with eosinophilic esophagitis (EoE) is lacking.

METHODS

This study included all Swedish adults with EoE without a record of previous cardiovascular disease (CVD) (1990-2017, N = 1546) with follow-up until 2019. Individuals with EoE were identified from prospectively recorded histopathology reports from all Swedish pathology departments (n = 28). EoE patients were matched at index date for age, sex, calendar year and county with up to five general population reference individuals (N = 7281) without EoE or CVD. Multivariable-adjusted hazard ratios (aHRs) for MACE (ischemic heart disease, congestive heart failure, stroke and cardiovascular mortality) were calculated using Cox proportional hazards models. Full sibling comparisons and adjustment for cardiovascular medication were performed.

RESULTS

During a median follow-up of 6.0 years, we observed 65 incident MACE in patients with EoE (6.4/1000 person-years (PY)) and 225 in reference individuals (4.7/1000 PY). EoE was not associated with a higher risk of MACE (aHR = 1.14, 95% CI = 0.86-1.51) or any of its components. No differences between age, sex and follow-up time were observed. The results remained stable in sensitivity analyses, including when adjusting for relevant cardiovascular medications and a full sibling comparison.

CONCLUSIONS

In this large population-based cohort study, patients with EoE had no increased risk of MACE compared to reference individuals and full siblings. The results are reassuring for patients with EoE.

Impact of inflammatory bowel disease on the risk of acute coronary syndrome: A Swedish Nationwide Cohort Study

BACKGROUND

There are conflicting data on the risk of acute coronary syndrome (ACS) in patients with inflammatory bowel disease (IBD). Only a few previous reports include patients diagnosed during the last decade.

AIM

To assess and compare the risk of ACS between patients with IBD and the general population.

METHODS

In this cohort study, we used nationwide registers to identify patients diagnosed with IBD in Sweden 2003-2021. Every patient was matched by birth year, sex, calendar year and area of residence with up to 10 general population comparators. The primary outcome was incident ACS. We used semi-parametric Cox proportional hazard models to estimate hazard ratios (HRs).

RESULTS

We identified 76,517 patients with IBD (Crohn's disease [CD], N = 22,732; ulcerative colitis [UC], N = 42,194 and IBD-unclassified, N = 11,591) and 757,141 comparators. During a median follow-up of 8 years, 2546 patients with IBD (37.5/10,000 person-years) were diagnosed with ACS compared with 19,598 (28.0/10,000 person-years) among comparators (HR 1.30; 95% confidence interval 1.24-1.35) after adjustments for confounding factors, and approximately one extra case of ACS in 100 IBD patients followed for 10 years. The highest HRs for ACS were in patients with elderly onset IBD (≥60 years) and among patients with CD or UC with extra-intestinal manifestations. No increased HRs were observed in patients diagnosed with IBD before the age of 40.

CONCLUSION

In this contemporary cohort of patients with IBD, exposed to modern IBD care, there was an increased risk for ACS compared with individuals from the general population.

Atherosclerosis as a Risk Factor of Inflammatory Bowel Disease: A Population-Based Case-Control Study

INTRODUCTION

Data suggest atherosclerotic-related inflammation may play a role in the pathogenesis of inflammatory bowel disease (IBD), but large-scale studies are missing.

METHODS

In this nationwide case-control study, we used the Swedish Patient Register and the Epidemiology Strengthened by histoPathology Reports in Sweden cohort to identify adult cases of incident IBD between 2002 and 2021, with each case matched to up to 10 general population controls. We used conditional logistic regression to calculate odds ratios (OR) for exposure to an atherosclerotic-related condition (myocardial infarction, thromboembolic stroke, or atherosclerosis itself) before being diagnosed with IBD.

RESULTS

There were a total of 56,212 individuals with IBD and 531,014 controls. Of them, 2,334 (4.2%) cases and 18,222 (3.4%) controls had a prior diagnosis of an atherosclerotic-related condition, corresponding to an OR of 1.30 (95% confidence interval [CI] 1.24-1.37). Results were statistically significant for both Crohn's disease (OR 1.37, 95% CI 1.26-1.48) and ulcerative colitis (OR 1.27, 95% CI 1.20-1.35) and for individuals who developed IBD at 40-59 years of age and 60 years or older. In addition, associations persisted when adjusting for underlying comorbidities, including the presence of immune-mediated diseases and prior aspirin and/or statin use. The highest odds of an atherosclerotic-related condition were seen in the 6-12 months before IBD diagnosis, though odds were increased even ≥5 years before. A higher magnitude of odds was also observed when having 2 or more atherosclerotic-related conditions when compared with having only 1 condition.

DISCUSSION

A history of an atherosclerotic-related condition is associated with increased odds of developing IBD, particularly among older adults. Future studies should investigate whether drugs targeting atherosclerotic-related inflammation may prevent IBD in higher-risk individuals.

Patients With Microscopic Colitis Are at Higher Risk of Major Adverse Cardiovascular Events: A Matched Cohort Study

BACKGROUND AND AIMS

Inflammatory diseases are associated with an increased risk of incident major adverse cardiovascular events (MACE). However, data on MACE are lacking in large population-based histopathology cohorts of microscopic colitis (MC).

METHODS

This study included all Swedish adults with MC without previous cardiovascular disease (1990-2017; N = 11,018). MC and subtypes (collagenous colitis and lymphocytic colitis) were defined from prospectively recorded intestinal histopathology reports from all pathology departments (n = 28) in Sweden. MC patients were matched for age, sex, calendar year, and county with up to 5 reference individuals (N = 48,371) without MC or cardiovascular disease. Sensitivity analyses included full sibling comparisons, and adjustment for cardiovascular medication and healthcare utilization. Multivariable-adjusted hazard ratios for MACE (any of ischemic heart disease, congestive heart failure, stroke, and cardiovascular mortality) were calculated using Cox proportional hazards modelling.

RESULTS

Over a median of 6.6 years of follow-up, 2181 (19.8%) incident cases of MACE were confirmed in MC patients and 6661 (13.8%) in reference individuals. MC patients had a higher overall risk of MACE outcomes compared with reference individuals (adjusted hazard ratio [aHR], 1.27; 95% confidence interval [CI], 1.21-1.33) and higher risk of its components: ischemic heart disease (aHR, 1.38; 95% CI, 1.28-1.48), congestive heart failure (aHR, 1.32; 95% CI, 1.22-1.43), and stroke (aHR, 1.12; 95% CI, 1.02-1.23) but not cardiovascular mortality (aHR, 1.07; 95% CI, 0.98-1.18). The results remained robust in the sensitivity analyses.

CONCLUSIONS

Compared with reference individuals, MC patients had a 27% higher risk of incident MACE, equal to 1 extra case of MACE for every 13 MC patients followed for 10 years.

Unsupervised representation learning improves genomic discovery and risk prediction for respiratory and circulatory functions and diseases

High-dimensional clinical data are becoming more accessible in biobank-scale datasets. However, effectively utilizing high-dimensional clinical data for genetic discovery remains challenging. Here we introduce a general deep learning-based framework, REpresentation learning for Genetic discovery on Low-dimensional Embeddings (REGLE), for discovering associations between genetic variants and high-dimensional clinical data. REGLE uses convolutional variational autoencoders to compute a non-linear, low-dimensional, disentangled embedding of the data with highly heritable individual components. REGLE can incorporate expert-defined or clinical features and provides a framework to create accurate disease-specific polygenic risk scores (PRS) in datasets which have minimal expert phenotyping. We apply REGLE to both respiratory and circulatory systems: spirograms which measure lung function and photoplethysmograms (PPG) which measure blood volume changes. Genome-wide association studies on REGLE embeddings identify more genome-wide significant loci than existing methods and replicate known loci for both spirograms and PPG, demonstrating the generality of the framework. Furthermore, these embeddings are associated with overall survival. Finally, we construct a set of PRSs that improve predictive performance of asthma, chronic obstructive pulmonary disease, hypertension, and systolic blood pressure in multiple biobanks. Thus, REGLE embeddings can quantify clinically relevant features that are not currently captured in a standardized or automated way.

Long-term risk of inflammatory bowel disease after endoscopic biopsy with normal mucosa: A population-based, sibling-controlled cohort study in Sweden

BACKGROUND

Although evidence suggests a persistently decreased risk of colorectal cancer for up to 10 years among individuals with a negative endoscopic biopsy result (i.e., normal mucosa), concerns have been raised about other long-term health outcomes among these individuals. In this study, we aimed to explore the long-term risk of inflammatory bowel disease (IBD) after an endoscopic biopsy with normal mucosa.

METHODS AND FINDINGS

In the present nationwide cohort study, we identified all individuals in Sweden with a lower or upper gastrointestinal (GI) biopsy of normal mucosa during 1965 to 2016 (exposed, n = 200,495 and 257,192 for lower and upper GI biopsy, respectively), their individually matched population references (n = 989,484 and 1,268,897), and unexposed full siblings (n = 221,179 and 274,529). Flexible parametric model estimated hazard ratio (HR) as an estimate of the association between a GI biopsy of normal mucosa and IBD as well as cumulative incidence of IBD, with 95% confidence interval (CI). The first 6 months after GI biopsy were excluded to avoid detection bias, surveillance bias, or reverse causation. During a median follow-up time of approximately 10 years, 4,853 individuals with a lower GI biopsy of normal mucosa developed IBD (2.4%) compared to 0.4% of the population references. This corresponded to an incidence rate (IR) of 20.39 and 3.39 per 10,000 person-years in the respective groups or 1 extra estimated IBD case among 37 exposed individuals during the 30 years after normal GI biopsy. The exposed individuals had a persistently higher risk of overall IBD (average HR = 5.56; 95% CI: 5.28 to 5.85), ulcerative colitis (UC, average HR = 5.20; 95% CI: 4.85 to 5.59) and Crohn's disease (CD, average HR = 6.99; 95% CI: 6.38 to 7.66) than their matched population references. In the sibling comparison, average HRs were 3.27 (3.05 to 3.51) for overall IBD, 3.27 (2.96 to 3.61) for UC, and 3.77 (3.34 to 4.26) for CD. For individuals with an upper GI biopsy of normal mucosa, the average HR of CD was 2.93 (2.68 to 3.21) and 2.39 (2.10 to 2.73), compared with population references and unexposed full siblings, respectively. The increased risk of IBD persisted at least 30 years after cohort entry. Study limitations include lack of data on indications for biopsy and potential residual confounding from unmeasured risk or protective factors for IBD.

CONCLUSIONS

Endoscopic biopsy with normal mucosa was associated with an elevated IBD incidence for at least 30 years. This may suggest a substantial symptomatic period of IBD and incomplete diagnostic examinations in patients with early IBD.

Antioxidant Properties of Gluten-Free Pasta Enriched with Vegetable By-Products

The only therapy for coeliac disease patients is to completely avoid foods containing gluten, a protein complex common in several small-grain cereals. However, many alternative gluten-free foods available on the market present nutritional deficiencies. Therefore, the aim of this research was to evaluate the composition and the antioxidant properties of gluten-free pasta enriched with 10% or 15% of tomato waste or linseed meal, two food industry by-products. The traits analysed were protein, lipid, ash and fibre content, heat damage, tocols, carotenoids and phenolics composition (by HPLC), antioxidant capacity, and pasta fracturability. The enriched pastas contained more fibre and lipids than the control, while the protein and ash values were similar. The addition of tomato and linseed waste improved tocols concentration but had no effect on carotenoids content. The free soluble polyphenols increase was similar for both by-products and proportional to the enrichment percentage, while the bound insoluble polyphenols were higher in linseed-enriched pastas. The samples with linseed meal showed the greatest antioxidant capacity and, at 10% addition, the highest fracturability value. In conclusion, the addition of tomato and linseed by-products significantly increases the presence of bioactive compounds (particularly polyphenols), improving the nutritional value of gluten-free pasta.

Cardiovascular Outcomes in Patients With Biopsy-proven Alcohol-related Liver Disease

BACKGROUND & AIMS

Patients with alcohol-related liver disease (ALD) frequently have risk factors for cardiovascular disease (CVD), but their long-term risk of CVD is not well-known, especially considering the competing risk of death from liver-related causes. It is further unknown if any excess risk varies across histological subgroups.

METHODS

We investigated the risk of CVD outcomes in 3488 persons with ALD and an available liver biopsy in Sweden between 1969 and 2016, compared with a matched reference population (n = 15,461). Administrative coding from national diagnostic and histopathology registers were used to define exposures and outcomes. Competing risk regression, taking non-CVD death into account and adjusting for potential confounders, was used to estimate subdistribution hazard ratios for incident CVD up until Dec 31, 2019.

RESULTS

At baseline, patients with ALD had a median age of 58 years, 64% were men, and 2039 (58%) had cirrhosis on histology. The incidence rate of CVD was 35.6 per 1000 person-years in ALD compared with 19.0 per 1000 person-years in reference individuals. ALD was associated with a 2-fold increased short-term risk for CVD compared with matched reference individuals (subdistribution hazard ratio during the first year after diagnosis, 2.29; 95% confidence interval, 1.79-2.95), but this risk decreased with time. Incidence rates of CVD were comparable across histological subgroups (ranging from 27.4 CVD cases per 1000 person-years in those with normal histology to 39.2 cases per 1000 person-years in those with cirrhosis).

CONCLUSIONS

Persons with biopsy-proven ALD have increased rates of CVD across histological subgroups compared with matched reference individuals, particularly just after ALD diagnosis. Active surveillance of modifiable CVD risk factors should be considered by clinicians treating patients with ALD.

Normal gastrointestinal mucosa at biopsy and subsequent cancer risk: nationwide population-based, sibling-controlled cohort study

Background

While individuals with normal gastrointestinal (GI) mucosa on endoscopy have a lower risk of colorectal cancer, risks of other cancers remain unexplored.

Methods

Through Sweden’s 28 pathology departments, we identified 415,092 individuals with a first GI biopsy with histologically normal mucosa during 1965–2016 and no prior cancer. These individuals were compared to 1,939,215 matched reference individuals from the general population. Follow-up began 6 months after biopsy, and incident cancer data were retrieved from the Swedish Cancer Register. Flexible parametric model was applied to estimate cumulative incidences and hazard ratios (HRs) for cancers. We also used full siblings (n = 441,534) as a secondary comparison group.

Results

During a median follow-up of 10.9 years, 40,935 individuals with normal mucosa (incidence rate: 82.74 per 10,000 person-years) and 177,350 reference individuals (incidence rate: 75.26) developed cancer. Restricting the data to individuals where follow-up revealed no cancer in the first 6 months, we still observed an increased risk of any cancer in those with a histologically normal mucosa (average HR = 1.07; 95%CI = 1.06–1.09). Although the HR for any and specific cancers decreased shortly after biopsy, we observed a long-term excess risk of any cancer, with an HR of 1.08 (95%CI = 1.05–1.12) and a cumulative incidence difference of 0.93% (95%CI = 0.61%-1.25%) at 30 years after biopsy. An elevated risk of gastric cancer, lung cancer, and hematological malignancy (including lymphoproliferative malignancy) was also observed at 20 or 30 years since biopsy. Sibling analyses confirmed the above findings.

Conclusion

Individuals with a histologically normal mucosa at biopsy and where follow-up revealed no cancer in the first 6 months, may still be at increased risk of cancer, although excess risks are small.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09992-5.

Normal Gastrointestinal Mucosa at Biopsy and Overall Mortality: Nationwide Population-Based Cohort Study

Background

Normal gastrointestinal (GI) mucosa on endoscopy has been linked to a lower risk of colorectal cancer (CRC) but its association to overall death is unknown.

Methods

We identified 466,987 individuals with a first GI biopsy 1965–2016 with normal mucosa (60.6% upper GI and 39.4% lower GI) through all Swedish pathology departments (n = 28). They were individually matched to 2,321,217 reference individuals without a GI biopsy and also compared to 505,076 full siblings. Flexible parametric models were applied to estimate hazard ratio (HRs) and 95% confidence interval (95% CI) for death.

Results

During a median follow-up of ~11 years, 85,859 (18.39%) of individuals with normal mucosa and 377,653 (16.27%) of reference individuals died. This corresponded to incidence rates of 147.56/10,000 vs 127.90/10,000 person-years respectively (rate difference: 19.66/10,000 person-years), with the multivariable-adjusted HR of 1.21 (95% CI: 1.20–1.22). Excess mortality was seen for both upper and lower biopsy with normal mucosa. Particularly higher HRs for death were seen in males, individuals biopsied when aged <40 years, those without a prior record of GI disease, and those with high education. Mortality risk was most increased in the first five years after biopsy (HR = 1.34; 95% CI: 1.32–1.36) but decreased thereafter. Having a GI biopsy with normal mucosa was associated with excess mortality from cardiovascular (CVD)disease (HR = 1.02; 95% CI: 1.01–1.03), cancer (HR = 1.58; 95% CI: 1.56–1.61), GI disease (HR = 1.65; 95% CI: 1.58–1.71), and other causes (HR = 1.10; 95% CI: 1.08–1.11). Sibling comparisons yielded similar results.

Conclusion

Compared with individuals without a GI biopsy, those with a normal GI biopsy due to clinical symptoms had a higher mortality particularly in the first five years after biopsy, and especially from GI disease and cancer.

Risk of Cancer in Biopsy-Proven Alcohol-Related Liver Disease: A Population-Based Cohort Study of 3410 Persons

BACKGROUND & AIMS

Persons with alcohol-related liver disease (ALD) are at an increased risk of death and liver-related endpoints, but the association with incident cancer is not well understood, and whether it differs across histopathological subgroups is undefined.

METHODS

We investigated the risk of cancer in 3,410 persons with a diagnosis of ALD and an available liver biopsy in Sweden between 1969-2016, compared to a matched reference population. Administrative coding from national registers and liver biopsy data were used to define exposure and outcome status. Competing risk regression, adjusted for available confounders and using non-cancer mortality as the competing risk, was used to estimate subdistribution hazard ratios (sHRs) for incident cancer.

RESULTS

At baseline, persons with ALD had a median age of 58.2 years, 67% were men, and 2,042 (60%) had cirrhosis. ALD was not associated with cancer in general (sHR = 1.01, 95%CI = 0.92-1.11), although the risk was increased in persons surviving ≥1 year (sHR = 1.19, 95% CI = 1.08-1.32). The risk of liver cancer was elevated sHR = 12.80, 95%CI = 9.38-17.45). HCC incidence among ALD persons with cirrhosis was 8.6 cases/1,000 person-years, corresponding to a cumulative incidence after 10 years of 5.0%.

CONCLUSIONS

Persons with biopsy-proven ALD that survive the initial time after diagnosis are at an elevated risk for cancer, in particular HCC compared with the general population. Although the risk for HCC was elevated, data do not suggest that routine surveillance for HCC in ALD cirrhosis is cost-effective.

Mortality in biopsy-proven alcohol-related liver disease: a population-based nationwide cohort study of 3453 patients

OBJECTIVE

Patients with alcohol-related liver disease (ALD) are at increased risk of death, but studies have rarely investigated the significance of histological severity or estimated relative risks compared with a general population. We examined mortality in a nationwide cohort of biopsy-proven ALD.

DESIGN

Population-based cohort study in Sweden comparing 3453 individuals with an International Classification of Disease (ICD) code for ALD and a liver biopsy from 1969 to 2017 with 16 535 matched general population individuals. Swedish national registers were used to ascertain overall and disease-specific mortality, starting follow-up at the latest of first ICD diagnosis or liver biopsy plus 3 months. Cox regression adjusted for relevant confounders was used to estimate HRs in ALD and histopathological subgroups.

RESULTS

Median age at diagnosis was 58 years, 65% were men and 52% had cirrhosis at baseline. Five-year cumulative mortality was 40.9% in patients with ALD compared with 5.8% in reference individuals. The risk for overall mortality was significantly increased (adjusted HR (aHR)=4.70, 95% CI 4.35 to 5.08). The risk of liver-related death was particularly high (43% of all deaths, aHR=167.6, 95% CI 101.7 to 276.3). Mortality was significantly increased also in patients with ALD without cirrhosis and was highest in the first year after baseline but persisted after ≥10 years of follow-up (aHR=2.74, 95% CI 2.37 to 3.16).

CONCLUSION

Individuals with biopsy-proven ALD have a near fivefold increased risk of death compared with the general population. Individuals with ALD without cirrhosis were also at increased risk of death, reaffirming the need to increase vigilance in the management of these individuals.

Celiac Disease: Extraintestinal Manifestations and Associated Conditions

Celiac disease is a common form of enteropathy with frequent extraintestinal manifestations (EIM). Misrecognition of these presentations may lead to significant delays in diagnosis. Any organ may be involved, either through an immune/inflammatory phenomenon, or nutritional deficiencies. Some EIM, such as gluten ataxia, may be irreversible if left untreated, but most will improve with a gluten-free diet. Knowledge of the various EIM, as well as the associated conditions which do not improve on a gluten-free diet, will avoid delays in the diagnosis and management of celiac disease and associated manifestations.

Epidemiology of Celiac Disease

Celiac disease is a common, chronic inflammatory disorder of the small intestine triggered by exposure to gluten in individuals with certain genetic types. This disorder affects people of any age or gender. Although often thought to be European in origin, it is now global in extent. Presentations are variable, from asymptomatic patients to severe malnutrition. Initial detection usually relies on celiac-specific serology, and confirmation often requires intestinal biopsy. There have been substantial increases in prevalence and incidence over the last 2 decades for reasons that are almost certainly environmental but for which there is no clarity as to cause.

Direct Costs in Patients with Celiac Disease in the USA: A Retrospective Claims Analysis

BACKGROUND

Celiac disease (CeD) is an autoimmune disease triggered by gluten ingestion.

AIM

We assessed total direct costs burden associated with CeD in patients with CeD versus patients without CeD using administrative claims data.

METHODS

Patients with CeD (cases) with ≥1 occurrences of CeD diagnosis were selected at a randomly chosen date (index date) from the OptumHealth Reporting and Insights database from 01/01/1998 through 03/31/2013. Cases were continuously enrolled throughout baseline (1 year before index date) and study (1 year after index date) periods. Cases were categorized as full remission and partial remission and matched 1:1 based on age, sex, region, index date, company, and employment status. Total all-cause and CeD-related costs were calculated.

RESULTS

A total of 12,187 cases were matched with an equal number of controls. Mean total all-cause costs were $12,217 in cases versus $4935 in controls (P < 0.0001). In full remission (N = 10,181 [83.5 %]) and partial remission (N = 2006 [16.5 %]) cases, mean total all-cause direct costs (cases versus controls) were $11,038 versus $4962 and $18,206 versus $4796, respectively. All-cause medical costs ($9839 for all cases, $8723 for full remission cases, $15,499 for partial remission cases) accounted for the majority of all-cause total costs and included outpatient costs ($6675; $6456; and $7785, respectively) and hospitalizations ($2776; $1963; and $6906, respectively). CeD-related medical costs were 13 and 27 % of all-cause medical costs for all cases and partial remission cases, respectively.

CONCLUSIONS

Patients with CeD and partial remission of CeD incurred significantly higher (2.5 and 3.8 times) total all-cause costs compared with matched controls.

Modified dachengqi decoction combined with conventional treatment for treating acute exacerbation of chronic obstructive pulmonary disease: a systematic review based on randomized controlled trials

Objective. This study intended to systematically evaluate the effectiveness and safety of modified Dachengqi Decoction (MDD) combined with conventional treatment for treating acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Method. An extensive search was performed within 6 English and Chinese electronic databases from inception to April 2012. Methodological quality was assessed according to Cochrane risk of bias assessment. Data were analyzed using Review Manager 5.1. Results. A total of 16 studies (involving 1112 patients) were included. The result showed that MDD and its modification combined with routine treatment were more effective in improving FEV1%pred, enhancing the significant effectiveness, reducing PCO2, and shortening duration of mechanical ventilation. Adverse events were reported in two trials with symptom of diarrhea, while no serious adverse effect was reported. Conclusion. Modified Dachengqi Decoction appears to be effective for treating AECOPD. However, more regular designed RCTs are needed because of insufficient methodological problems.