Table 2.

Clinical Heterogeneity of Studies in Review

Characteristic	n (%)
Definition of “elderly”
60	1 (5)
61	1 (5)
65	6 (30)
70	7 (35)
80	5 (25)
Number of age groups defined as “elderly”
1	5 (25)
2	9 (45)
3	3 (15)
4	2 (10)
6	1 (5)
Procedure type
Major abdominal procedurea	5 (25)
Colon, malignant	5 (25)
Colon, mixed benign and malignantb	5 (25)
Colon, benign	3 (15)
Perforated peptic ulcer	1 (5)
Diagnosis of acute abdomen	1 (5)
Included elective cases for comparison	6 (30)
Method for defining “emergency” cases
Standardized database definitions	7 (35)
After nonelective admission	5 (25)
Within 12, 24, or 72 hours of admission	2 (10)
Defined by disease process	2 (10)
Defined emergence by surgeon	1 (5)
No specific definition provided	3 (15)
Included younger individuals for comparison	12 (60)
Age range of “younger” comparison participantsc
16–39	1 (8)
16–64	1 (8)
17–69	1 (8)
18–50	1 (8)
18–55	1 (8)
18–69	1 (8)
18–79	1 (8)
20–64	1 (8)
23–69	1 (8)
<70d	1 (8)
<80d	1 (8)
65–79e	1 (8)
Mortality measuref
In-patient	5 (25)
30-day	15 (75)
1-year	3 (15)
>1-year	1 (1)

^aIncluding exploratory laparotomy.

^bProportion of malignant cases ranged from 18% to 54%.

^cn = 12.

^dLower age bound not defined.

^eOlder comparison group age >79.

^fBecause each study may have had more than one mortality measure, these proportions add up to more than 100%.