Serum creatinine/cystatin C ratio is a surrogate marker for sarcopenia in patients with idiopathic pulmonary fibrosis

Table 2 Relationships between serum creatinine/cystatin C ratio and clinical parameters

	r	95% CI	P value
Age, years	− 0.56	− 7.31 to − 3.25	< 0.001
Body mass index, kg/m²	0.42	0.16–0.64	< 0.01
GAP index	− 0.41	− 0.62 to 0.14	< 0.01
FVC, % predicted, %	0.26	− 0.28 to 0.51	0.07
DL_CO, % predicted, %	0.18	− 1.1 to 0.45	0.21
PaO₂, mmHg	0.54	0.19–0.66	< 0.001
6MWT
Distance, m	0.42	0.15–0.63	< 0.01
Lowest SpO₂, %	0.31	0.026–0.55	< 0.05
SARC-F	− 4.82	− 6.76 to − 2.24	< 0.001
mMRC	− 0.54	− 0.72 to − 0.30	< 0.001
CAT	− 0.38	− 0.61 to − 0.99	< 0.01
K-BILD
Psychological	0.27	− 0.20 to 0.52	0.06
Breathlessness and activities	0.52	0.27–0.71	< 0.001
Chest symptoms	0.25	− 0.05 to 0.50	0.09
Total	0.4	0.13–0.61	< 0.005

GAP gender, age, and physiology, FVC forced vital capacity, DL_CO diffuse capacity of the lung for carbon monoxide, PaO₂ partial pressure of oxygen, 6 MWT 6-min walk test, SpO₂ oxygen saturation by pulse oximetry, ASMI appendicular skeletal muscle index, SARC-F strength, assistance in walking, rising from a chair, climbing stairs, and falls, mMRC modified Medical Research Council, CAT chronic obstructive pulmonary disease assessment test, K-BILD King's brief interstitial lung disease

ISSN: 1471-2466