Factor analysis identifies subgroups of constipation

Table 1 Factor loadings derived from the rotated factor matrix

	Factor loading	Percent variance
Factor 1: Straining		17.3
Strain hard: How often	0.82
Straining: How bad usually	0.80
Straining: How long	0.76
Straining: How often	0.71
How long to bowel motions take	0.59
How often incomplete evacuation	0.55
How often unsuccessful attempts	0.52
Frequency of any bowel problems	0.47
How troubling is constipation	0.41
Change positions: How often	0.35
Factor 2: Pain frequency and severity		8.4
Abdominal pain: How often	0.80
Pain in belly: Past 3 mo	0.79
Abdominal pain: Severity	0.79
Abdominal pain: Length	0.65
Rectal mucus: How often	0.41
Rectal pain: How often	0.39
Pain in belly: Past 12 mo	-0.58
Factor 3: Duration of constipation		6.5
Constipation: How many years	0.89
Straining: How many years	0.87
Abdominal pain: First occurrence	0.57
Factor 4: Irritable bowel syndrome symptoms		5.6
Abdominal pain: Improved after bowel motion	0.75
Abdominal pain: Improved after passing gas	0.70
Experience lower abdominal pain	0.63
Bowel motions: Harder than usual past 12 mo	0.40
Factor 5: Urge frequency		4.1
Urge for bowel motion: How often	0.72
Perceive an urge before attempt to open bowels	0.68
Visits to toilet: How often	0.56
Urgency for bowel motion: How often	0.42
Factor 6: Diarrhea frequency		3.8
Loose/watery stool: How often	0.75
Pebble-like stool: How often	-0.42
Rectal disimpaction: How often required	-0.45
Hard/lumpy stool: How often	-0.63
Factor 7: Alternating between diarrhea and constipation		3.4
Usually alternating	0.87
Usually constipated	-0.86
Factor 8: Bloating frequency		3.2
Stomach swelling in the last 12 mo: How often	0.71
Felt bloated in the last 12 mo: How often	0.68
Felt blocked: How often	0.47
Factor 9: Laxative efficacy		2.9
Laxative use: Longest gap between taking and bowel motion	0.70
Bowel motions: Fewer than usual past 12 mo	0.56
Laxative use: How often	0.44
Factor 10: Rectal urgency		2.7
Urge from rectum	0.89
Urge from abdomen and rectum	-0.80
Factor 11: Bowel motion frequency		2.6
Longest gap between bowel motions	0.81
Usual bowel frequency	-0.56
Factor 12: Change in bowel frequency		2.4
Bowel motions: More than usual past 12 mo	0.74
Bowel motions: Looser than usual past 12 mo	0.62
Factor 13: Abdominal urge		2.3
Experience an urge from abdomen	0.89
Factor 14: Diarrhea predominance		2.2
Usually experience diarrhea	0.79
Factor 15: Antecedent to constipation		2.0
An antecedent for the constipation	0.71
Experience upper abdominal pain	0.51
Total (1-15)		69.3

Table 2 Summary of the proportion of patients within each cluster who were positive for constipation¹ or irritable bowel syndrome on the basis of Rome III criteria, as well as proportions in each group with slow transit constipation

	Clusters (4-fold solution)
	1(n = 71)	2(n = 44)	3(n = 34)	4(n = 43)
Rome III constipation
Yes	84.50%	77.30%	58.80%	72.10%
Rome III IBS
Yes	52.10%	27.30%	20.60%	53.50%
Outlet dysfunction
Yes	52.10%	56.80%	52.90%	48.80%
Colonic transit	n = 43	n = 28	n = 16	n = 29
Delayed transit	74.40%	71.40%	62.50%	79.30%
Normal transit	25.60%	28.60%	37.50%	20.70%

¹With the exception that symptoms were assessed irrespective of laxative usage. IBS: Irritable bowel syndrome.