Williams et al developed a model and nomogram for estimating the risk of unplanned readmission following major surgery. This can help to identify a patient who may benefit from more aggressive management. The authors are from the University of Virginia at Charlottesville.
Patient selection: status post major surgery
Outcome: unplanned readmission within 30 days of procedure
Parameters:
(1) admission status (inpatient or outpatient)
(2) ASA classification
(3) wound classification
(4) therapy with corticosteroids for a chronic condition
(5) preoperative dialysis
(6) elective surgery
(7) diabetes mellitus
(8) disseminated cancer
(9) discharge destination
(10) total time for operation in minutes
Parameter |
Finding |
Points |
admission status |
outpatient |
0 |
|
inpatient |
51 |
ASA classification |
ASA 1 |
0 |
|
ASA 2 |
43 |
|
ASA 3 |
81 |
|
ASA 4 |
100 |
|
ASA 5 |
59 |
|
none assigned |
93 |
wound classification |
clean |
0 |
|
clean/contaminated |
21 |
|
contaminated |
25 |
|
infected |
25 |
therapy with corticosteroids |
no |
0 |
|
yes |
40 |
preoperative dialysis |
no |
0 |
|
yes |
51 |
elective surgery |
no |
29 |
|
unknown |
0 |
|
yes |
7 |
diabetes mellitus |
no |
0 |
|
non-insulin (oral agent) |
5 |
|
insulin dependent |
24 |
disseminated cancer |
no |
0 |
|
yes |
32 |
discharge destination |
facility now home (nursing home, etc) |
42 |
|
home |
1 |
|
rehabilitation center |
19 |
|
separate acute care |
0 |
|
skilled or unskilled care |
24 |
operation time |
< 60 minutes |
0 |
|
60 to 119 minutes |
7 |
|
120 to 179 minutes |
19 |
|
180 to 239 minutes |
31 |
|
>= 240 minutes |
52 |
where:
• Admission status may apply to status at the time of the original surgery.
• The value for an assigned ASA classification seems high.
• The value of ASA 5 is less than an ASA 4 may reflect selection of patients for surgery or postoperative mortality.
• The points for unknown response to elective surgery is less than yes or no.
total score =
= SUM(points for all 10 parameters)
Interpretation:
• minimum score: 0
• maximum score: 446
• The higher the score the greater the risk for unplanned readmission.
X =
= (0.0132 * (score)) - 4.7672
probability of unplanned readmission =
= 1 / (1+ EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.70.