Luo et al reported a nomogram for predicting obstructive sleep apnea. This can help to reduce the need to unnecessary sleep studies. The authors are from Guilin Medical College, Southern Medical University Guangzhou, Osaka University and Duke University.
Patient selection: suspected obstructive sleep apnea
Parameters:
(1) course of disease in months
(2) lack of energy
(3) difficulty falling asleep
(4) smoking
(5) waist circumference in cm
points for disease course =
= 0.0495 * (months)
points for waist circumference =
= (0.7692 * (circumference)) - 46.1538
|
Parameter
|
Finding
|
Points
|
|
lack of energy
|
no
|
0
|
|
|
yes
|
13
|
|
difficulty falling asleep
|
no
|
13
|
|
|
yes
|
0
|
|
smoking
|
no
|
0
|
|
|
yes
|
8
|
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 163.7
value of X =
= (0.09429 * (score)) - 4.588
probability of moderate or severe obstructive sleep apnea =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.80.
