Prevalence of alpha-1-antitrypsin deficiency carriers in a population with and without colonic diverticula. A multicentre prospective case-control study: the ALADDIN study

Genetic, epigenetic and environmental factors in diverticular disease: systematic review

BACKGROUND

Diverticulosis is a normal anatomical variant of the colon present in more than 70% of the westernized population over the age of 80. Approximately 3% will develop diverticulitis in their lifetime. Many patients present emergently, suffer high morbidity rates and require substantial healthcare resources. Diverticulosis is the most common finding at colonoscopy and has the potential for causing a significant morbidity rate and burden on healthcare. There is a need to better understand the aetiology and pathogenesis of diverticular disease. Research suggests a genetic susceptibility of 40-50% in the formation of diverticular disease. The aim of this review is to present the hypothesized functional effects of the identified gene loci and environmental factors.

METHODS

A systematic literature review was performed using PubMed, MEDLINE and Embase. Medical subject headings terms used were: 'diverticular disease, diverticulosis, diverticulitis, genomics, genetics and epigenetics'. A review of grey literature identified environmental factors.

RESULTS

Of 995 articles identified, 59 articles met the inclusion criteria. Age, obesity and smoking are strongly associated environmental risk factors. Intrinsic factors of the colonic wall are associated with the presence of diverticula. Genetic pathways of interest and environmental risk factors were identified. The COLQ, FAM155A, PHGR1, ARHGAP15, S100A10, and TNFSF15 genes are the strongest candidates for further research.

CONCLUSION

There is increasing evidence to support the role of genomics in the spectrum of diverticular disease. Genomic, epigenetic and omic research with demographic context will help improve the understanding and management of this complex disease.

Alpha-1-antitrypsin deficiency (carrier) as possible risk factor for development of colonic diverticula. A multicentre prospective case-control study: the ALADDIN study

AIM

Connective tissue changes due to ageing or diseases leading to changes in the colonic wall are one theory for the development of diverticula. Alpha-1-antitrypsin (A1AT), a protease inhibitor that protects connective tissue, possibly plays a role in the aetiology of diverticulosis. The aim of this study was to explore associations between the development of diverticula and A1AT deficiency.

METHODS

This was a multicentre prospective case-control study. A total of 221 patients aged ≥ 60 years with acute abdominal pain undergoing abdominal CT were included and analysed. Patients with diverticula were defined as the research group, patients without diverticula as controls. Genotype analysis for A1AT deficiency was performed.

RESULTS

Twenty-six of 221 (11.8%) patients were diagnosed with (being a carrier of) A1AT deficiency. A non-significant difference in prevalence between patients with and without diverticula was found, 20 (13.9%) of 144 vs 6 (7.8%) of 77, respectively, with a crude OR of 1.9 (95% CI 0.7-5.0; P = 0.186) and after adjustment for confounders an adjusted OR of 1.5 (95% CI 0.5-4.0; P = 0.466). A non-significant difference in 30-day mortality rate from acute diverticulitis between A1AT deficient patients (or carriers) and those without was observed: two (22.2%) of nine patients with A1AT deficiency vs 1 (1.8%) of 55 without.

CONCLUSION

We found no convincing evidence that A1AT deficiency plays a role in the aetiology of diverticulitis, although deficient patients and carriers had a higher mortality when experiencing diverticulitis. Diverticulitis is a multifactorial disease and larger numbers may be needed to explore the role of A1AT deficiency among other contributing factors.

Meta-analysis of the demographic and prognostic significance of right-sided versus left-sided acute diverticulitis

AIM

The aim of this work was to compare demographic factors, outcomes and prognosis for right-sided versus left-sided acute colonic diverticulitis.

METHOD

We searched MEDLINE, CINAHL, EMBASE, CENTRAL, Scopus and unpublished literature to identify all observational studies comparing demographic factors and outcomes of right-sided versus left-sided acute colonic diverticulitis (PROSPERO registration number CRD42020180075). We used the QUIPS tool to assess the risk of bias of included studies. Random effects modelling was applied to calculate pooled outcome data.

RESULTS

Analysis of 2933 patients from nine studies suggests that right-sided diverticulitis affects younger patients [mean difference (MD)  -14.16 (-17.19, -11.14), P < 0.00001] and more male patients [odds ratio (OR) 1.33 (1.04, 1.71), P = 0.02] compared with left-sided diverticulitis. Smoking [OR 2.23 (1.50, 3.32), P < 0.0001], alcohol consumption [OR 1.85 (1.26, 2.71), P = 0.002] and comorbidity [OR 0.21 (0.15, 0.30), P < 0.00001] were more common in patients with right-sided diverticulitis. The risk of complicated diverticulitis was lower in the right-sided group [OR 0.21 (0.08, 0.55), P = 0.001]. More patients in the right-sided diverticulitis group had modified Hinchey Stage I disease [OR 10.21 (3.34, 31.22), P < 0.0001] while more patients in the left-sided group had Stage II [OR 0.19 (0.10, 0.38), P < 0.00001], Stage III [OR 0.08 (0.01, 0.54), P = 0.009] or Stage IV disease [OR 0.02 (0.00, 0.08), P < 0.00001]. Right-sided diverticulitis was associated with a lower risk of recurrence [OR 0.49 (0.25, 0.98), P = 0.04], failure of conservative management [OR 0.14 (0.04, 0.43), P = 0.0006], the need for emergency surgery [OR 0.13 (0.05, 0.36), P < 0.00001] and a shorter length of hospital stay [MD -1.70 (-3.08, -0.33), P = 0.02].

CONCLUSION

Right-sided acute diverticulitis predominantly affects younger male patients compared with left-sided disease and is associated with favourable outcomes as indicated by the lower risk of complications, failure of conservative management, need for emergency surgery, recurrence and shorter length of hospital stay. More studies are required to compare the postoperative outcomes in patients with right-sided and left-sided diverticulitis undergoing emergency surgery.