Gronbeck et al reported a nomogram for predicting inpatient status following a primary total knee arthroplasty (TKA). The authors are from the University of Connecticut.
Patient selection: age >= 65 years (Medicare0aged)
Parameters:
(1) age in years
(2) body mass index (BMI)
(3) hypertension
(4) COPD
(5) anemia
(6) metastatic cancer
(7) bleeding disorder
(8) dyspnea
(9) chronic kidney disease
(10) diagnosis
(11) type of anesthesia
(12) procedure length in minutes
(13) sex
(14) race
(15) current smoker
(16) chronic steroid use
(17) ASA status
(18) functional status
(19) admitted from a facility
(20) diabetes
points for age =
= MIN(10.03, (0.0055462 * ((age)^2)) - (0.32353 * (age)) - 2.4403)
|
BMI |
Points |
|
< 25 |
0 |
|
25 to 40 |
(0.01072 * ((BMI)^2)) - (0.4766 * (BMI)) + 5.978 |
|
> 40 |
4.09 |
|
Parameter |
Finding |
Points |
|
hypertension |
no |
0 |
|
|
yes |
0.31 |
|
COPD |
no |
0 |
|
|
yes |
2.89 |
|
anemia |
no |
0 |
|
|
yes |
2.86 |
|
metastatic cancer |
no |
0 |
|
|
yes |
5.89 |
|
bleeding disorder |
no |
0 |
|
|
yes |
2.34 |
|
dyspnea |
no |
0 |
|
|
yes |
1.62 |
|
chronic kidney disease |
no |
0 |
|
|
yes |
2.55 |
|
diagnosis |
post traumatic arthritis |
0 |
|
|
osteoarthritis |
2.40 |
|
|
inflammatory |
2.98 |
|
|
osteonecrosis |
4.74 |
|
type of anesthesia |
spinal |
0 |
|
|
general |
3.97 |
|
procedure length |
<= 100 minutes |
0 |
|
|
> 100 minutes |
3.73 |
|
sex |
male |
0 |
|
|
female |
5.11 |
|
race |
Asian |
0 |
|
|
Black |
0.83 |
|
|
White |
0.46 |
|
|
other |
5.19 |
|
current smoker |
no |
0 |
|
|
yes |
0.90 |
|
chronic steroid use |
no |
0 |
|
|
yes |
1.29 |
|
ASA |
1 or 2 |
0 |
|
|
3 to 5 |
1.11 |
|
functional status |
independent |
0 |
|
|
dependent |
6.06 |
|
admitted from a facility |
no |
0 |
|
|
yes |
4.25 |
|
diabetes |
no |
0 |
|
|
yes |
1.29 |
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 76.58
value of X =
= (0.1104 * (score)) - 0.9526
probability of inpatient status =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.66.
Specialty: Surgery, orthopedic
