Table 3.

The probability of remaining at work for at least three, six and nine years

Variable	Over 3 years	Over 6 years	Over 9 years
	(n = 119)	(n = 92)	(n = 59)
1. Age at the time of CABG
≤ 50	LR = 6.54	LR = 3.25	LR = 2.42
50 – 54	LR = 3.80	LR = 1.24	(LR = 0.20)
≥ 55	LR = 0.68	LR = 0.37	(LR = 0.01)
2. Postoperative cardiac symptoms
No	LR = 1.11		LR = 1.08
Yes	LR = 0.51		LR = 0.51
3. Height
< 175	LR = 0.59	LR = 0.58
175 – 179	LR = 1.43	LR = 1.80
180-	LR = 6.29	LR = 2.13
4. Being married
No	LR = 3.51	LR = 1.60	LR = 1.14
Yes	LR = 0.88	LR = 0.93	LR = 0.98
5. Diagnosed DM
No	LR = 0.92	LR = 1.03	LR = 1.04
Yes	LR = 2.59	LR = 0.80	LR = 0.70
6. Participation in household work
Daily		LR = 1.25	LR = 1.26
Less often		LR = 0.58	LR = 0.51
Precision of the model
False-Positive	10	18	15
False-Negative	9	17	13
Sensitivity	55%	63%	82%
Specificity	92%	82%	78%
Correct predictions	86%	75%	80%

In this model, the individual probability of remaining at work (calculated one year postoperatively) is as follows:

The patient's likelihood ratio (LR) of each of six characteristics is multiplied. The greater LR, the better is the possibility of remaining at work. If the total LR is greater than 1.00, the probability of remaining at work is more than 50% for the given time (3 y, 6 y, or 9 y). Patients in age groups marked in parenthesis may remain at work for over the age of 60.

LR may be expressed as probability as follows: p = 100 * LR/(1+LR).