Table 1.

Studies evaluating the natural history of acute diverticulitis

Ref.	No. of patients	Type of study	FU	Recurrence rate	Comments
Lahat et al[38], 2013	261	Prospective	88 mo	21.5%	21% operated, 46.6% asymptomatic
Buchs et al[17], 2013	280	Prospective	24 mo	16.4%	RF: CRP > 240
Humes and West[35], 2012	2950	Population-based cohort study	7.99 yr	-	Risk of fistula correlates to the number of prior episodes of diverticulitis
Binda et al[36], 2012	743	Multicenter, retro-prospective	10.7 yr	17.2%1	RF: < 40 yr, 3 episodes
Hall et al[16], 2011	672	Retrospective	42.8 mo	36%	RF: Family history, length of involved colon > 5 cm, retroperitoneal abscess
Mäkelä et al[20], 2010	555	Retrospective	-	42%	38% of recurrence diagnosed on clinical findings
Eglinton et al[26], 2010	320	Retrospective	101 mo	18.8%	4.7% more than one recurrent episode
Pittet et al[19], 2009	271	Retrospective	-	25%	Similar severity
Mueller et al[48], 2005	252	Retrospective	89 mo	47% (with 10% readmitted)	Based on symptoms
Anaya and Flum[27], 2005	25058	Cohort study, retrospective	-	19%	RF: < 50 yr, number of recurrent episodes
Broderick-Villa et al[28], 2005	3165 (2366 managed conservatively)	Cohort study, retrospective	8.9 yr	13.3%	RF: < 50 yr, charlson comorbidity index ≥ 1
Biondo et al[40], 2002	327	Retrospective	24-90 mo	15.9%	Age not a RF
Chautems et al[15], 2002	118	Prospective	9.5 yr	31%	Considering only patients undergoing an operation
Somasekar et al[34], 2002	108	Two-center, retrospective	-	2.7%1	Only patients with complicated disease
Mäkelä et al[43], 1998	366	Retrospective	-	22%	RF: < 50 yr, male
Ambrosetti et al[44], 1997	300	Prospective	46 mo	2%	RF: Radiological signs of complicated first episode
Parks[14], 1969	317	Retrospective	-	24.6%	Only readmitted patients

¹If medically treated (vs 5.8% if surgically treated; P < 0.001); 22.7% of the studied population (complicated diverticulitis) was known for a previous acute diverticulitis. FU: Follow-up; RF: Risk factor; CRP: C-reactive protein.