NT-proBNP <95 ng/l can exclude pulmonary hypertension on echocardiography at diagnostic workup in patients with interstitial lung disease

Figures & data

Fig. 1 Flow chart showing the number of patients included in final analysis and the results of echocardiography in the respective subgroups, ILD, interstitial lung disease; Echo, echocardiography; PH, pulmonary hypertension; EF, left ventricular ejection fraction.

Fig. 2 The values of NT-proBNP in patients with and without PH (pulmonary hypertension) on echocardiography. The vertical line at 95 ng/l. Error bars represent the median and interquartile range. p=0.0003.

Table 1 Diagnoses and comorbidity in the full cohort and the 118 patients included in the final analysis

	Full cohort (n=148)	Patients in analysis (n=118)
Diagnosis n (percent)
IPF	48 (32)	43 (36)
NSIP	8 (5)	8 (7)
DIP	4 (3)	3 (3)
Hypersensitivity  pneumonitis	5 (3)	4 (3)
ILD related to collagen  vascular disease	13 (9)	11 (9)
Other ILD	40 (27)	25 (21)
Unclassifiable ILD	30 (20)	24 (20)
Co-morbidity
Chronic left heart failure^a	10 (7)	9 (8)
Ischemic heart disease	13 (9)	13 (10)
Atrial fibrillation	13 (9)	11 (9)
Diabetes	4 (3)	3 (3)

IPF, idiopathic pulmonary fibrosis; NSIP, non-specific interstitial pneumonia; DIP, desquamative interstitial pneumonia; ILD, interstitial lung disease.

^aSome of these were well treated and had normal left ventricular ejection fractions.

Table 2 Demographics, lung function parameters, 6-min walk test and NT-proBNP

	Total (n=148)	Included in analysis (n=118)	Excluded from analysis (n=30)	Echo performed (n=123)	No echo (n=25)	No PH on echo (n=111)	PH on echo (n=12)
Age (years)	64.5	66 (64–69)	55 (48–62)^a	66 (64–68)	54 (46–62)^b	66 (64–69)	69 (63–76)
Female (percent)	39	40	30	32	40	38	58
TLC (percentage of expected)	78 (75–82)	78 (75–81)	80 (72–89)	77 (74–81)	84 (76–94)	78 (74–81)	73 (65–81)
DLCO (percentage of expected)	51 (48–55)	49 (45–52)	61 (50–70)^a	48 (45–51)	66 (56–77)^b	49 (46–52)	40 (27–53)
FEV1 (percentage of expected)	80 (76–84)	80 (77–84)	84 (75–93)	79 (76–83)	85 (76–95)	78 (76–84)	75 (59–91)
FVC (percentage of expected)	92 (77–107)	88 (74–101)	84 (74–94)	87 (74–100)	87 (76–98)	88 (74–102)	78 (63–93)
6MWT distance (meters)	433 (410–455)	420 (396–444)	488 (431–543)^a	416 (392–440)	518 (463–573)^b	424 (399–448)	327 (237–417)^c

Echo, echocardiography; TLC, total lung capacity; DL_CO, diffusion capacity; FEV1, forced expiratory capacity in 1 sec; FVC, forced vital capacity; 6MWT, 6-minute walk test.

Data are expressed as means with 95% confidence intervals, unless otherwise stated.

^a p<0.05 versus included in analysis.

^b p<0.05 versus echo performed.

^c p<0.05 versus no PH on echo.