Identifying Primary Spontaneous Pneumothorax from Administrative Databases: A Validation Study

Table 2

Distribution of patients with a main diagnosis code of pneumothorax according to age group.

Category	0 to 39 years	40 years and over	Total
Number of patients	95	55	150
Main diagnosis code
J930, spontaneous tension pneumothorax	2	2	4
J931, other spontaneous pneumothorax	46	11	57
J938, other pneumothorax	2	2	4
J939, pneumothorax, unspecified	45	40	85
Chart review
Primary spontaneous pneumothorax	74	16	90
Secondary pneumothorax	17	37	54
Absence of pneumothorax	4	2	6
Administrative data algorithm
Primary spontaneous pneumothorax	83	28	111
Secondary pneumothorax^†	12	27	39
Suspected etiology: chronic condition	5	18	23
Suspected etiology: acute condition	7	6	13
Suspected etiology: Iatrogenic	3	10	13

More than one suspected etiology may be identified for each patient.