The positive predictive value of spontaneous subarachnoid hemorrhage diagnoses in the Danish National Patient Register

Figures & data

Figure 1 Flowchart for study of patients registered in the Danish National Patient Register (DNPR) with a diagnosis of non-traumatic subarachnoid hemorrhage (ntSAH).

Abbreviations: ntSAH, non-traumatic subarachnoid hemorrhage; n, number; SAH, subarachnoid hemorrhage.

Table 1 Sub-group characteristics of selected groups with confirmed non-traumatic subarachnoid hemorrhage registered in the Danish National Patient Register

Validated ntSAH n=537	% (95% CI)	Sex	% (n)	95% CI	Age (median)	IQR
Perimesencephalic hemorrhage (n=28)	5.2 (3.4–7.1)	F	32.1 (9)	14.8–49.4	63.0	43–71
M	67.9 (19)	50.5–85.1	52.0	43–65
Vascular malformation (n=7)	1.3 (0.3–2.3)	F	14.3 (1)	0.0–40.0	33.0	33–33
M	85.7 (6)	59.8–100.0	63.5	56–71
Prehospital cardiac arrest (n=12)	2.2 (1.0–3.5)	F	58.3 (7)	30.4–86.2	62.0	58–66
M	41.7 (5)	13.7–69.6	51.0	42–58
Recurrent ntSAH (n=8)	1.5 (0.5–2.5)	F	75.0 (6)	45.0–100.0	56.0	48–76
M	25.0 (2)	0.0–55.0	53.0	36–70

Abbreviations: ntSAH, non-traumatic subarachnoid hemorrhage; CI, Confidence interval; n, number; IQR, inter quartile range; F, female; M, male.

Table 2 Characteristics of patients found not to have had non-traumatic subarachnoid hemorrhage despite being registered with this in the Danish National Patient Register

Not ntSAH n=305	% (n)	95% CI	Age (median)	IQR
Overall	36.2 (305)	33.0–39.5	64.0	48–75
Traumatic SAH	40.0 (122)	34.5–45.5	69.0	53–81
Parenchymal hemorrhage	14.5 (45)	10.8–18.7	68.0	60–82
ntSAH suspected but dismissed	18.9 (57)	14.3–23.0	51.0	33–64
ntSAH never suspected	11.5 (35)	7.9–15.0	72.0	49–79
Scheduled outpatient exam after SAH/scheduled aneurysm surgery	14.8 (45)	10.8–18.7	58.0	47–63
ntSAH suspected developed on admitted patient, dismissed	0.3 (1)	0.0–1.0	67.0	67–67

Abbreviations: ntSAH, non-traumatic subarachnoid hemorrhage; n, number; CI, confidence interval; IQR, inter quartile range; SAH, subarachnoid hemorrhage.

Table 3 Characteristics of patients registered with non-traumatic subarachnoid hemorrhage in the Danish National Patient Register that were not available for double review

Not accessible n=32	Sex	n	Age (median)	IQR
Records only accessible once (n=21)	F	13	73.0	42–83
	M	8	57.0	47–66
Medical records not found (n=11)	F	8	72.0	54–84
	M	3	64.0	51–87

Abbreviations: n, number; IQR, inter quartile range; F, female;M, male.

Figure S1 Case Report Form as used by the investigators for data collection if non-traumatic subarachnoid hemorrhage could not be confirmed.Abbreviations: DNPR, The Danish National Patient Register; SAH, subarachnoid hemorrhage; ntSAH, non-traumatic subarachnoid hemorrhage.