The Electronic Frailty Index is Associated with Increased Infection and All-Cause Mortality Among Older Patients with Primary Lung Cancer: A Cohort Study

Figures & data

Table 1 Characteristics of Study Population

	Overall	Non-Frailty	Frailty	P value^†	SMD^†
Number of patients	997	801	196
Male (%)	710 (71.2)	559 (69.8)	151 (77.0)	0.055	0.165
Age (years; mean (SD))	66.07 (4.90)	65.87 (4.84)	66.85 (5.06)	0.013	0.197
BMI (kg/m^2; mean (SD))	22.61 (3.00)	22.56 (2.77)	22.78 (3.81)	0.355	0.066
Marriage (%)				0.585	0.089
Divorced	8 (0.8)	7 (0.9)	1 (0.5)
Married	965 (96.8)	773 (96.5)	192 (98.0)
Widowed	24 (2.4)	21 (2.6)	3 (1.5)
Occupation (%)				0.792	0.103
Technician/worker	56 (5.6)	46 (5.7)	10 (5.1)
Civil Servants	76 (7.6)	62 (7.7)	14 (7.1)
Farmer	124 (12.4)	96 (12.0)	28 (14.3)
Retiree	234 (23.5)	184 (23.0)	50 (25.5)
Others	507 (50.9)	413 (51.6)	94 (48.0)
Alcohol (%)				0.603	0.079
Always	198 (19.9)	161 (20.1)	37 (18.9)
Never	586 (58.8)	474 (59.2)	112 (57.1)
Sometimes	213 (21.4)	166 (20.7)	47 (24.0)
Smoke index (median [IQR])	20.00 [0.00, 40.00]	15.00 [0.00, 40.00]	25.00 [0.00, 45.75]	<0.001	0.307
Smoke (%)				0.001	0.316
Non-smoker	385 (38.6)	332 (41.4)	53 (27.0)
Former smoker	299 (30.0)	234 (29.2)	65 (33.2)
Current smoker	313 (31.4)	235 (29.3)	78 (39.8)
Infection (%)	84 (8.4)	56 (7.0)	28 (14.3)	0.002	0.238
Gastrointestinal reactions (%)	56 (5.6)	46 (5.7)	10 (5.1)	0.86	0.028
Chemotherapy discontinuation (%)	22 (2.2)	14 (1.7)	8 (4.1)	0.085	0.139
Abnormal liver function (%)	67 (6.7)	52 (6.5)	15 (7.7)	0.672	0.045
Bone suppression (%)	174 (17.5)	130 (16.2)	44 (22.4)	0.051	0.158
Hospitalization (days; median [IQR])	13.00 [9.00, 19.00]	13.00 [9.00, 19.00]	15.00 [11.00, 22.00]	0.003	0.231
Histology (%)				<0.001	0.306
Adenocarcinoma	708 (71.0)	589 (73.5)	119 (60.7)
Squamous carcinoma	149 (14.9)	116 (14.5)	33 (16.8)
Small cell carcinoma	140 (14.0)	96 (12.0)	44 (22.4)
Chemotherapy regimen (%)	903 (90.6)	730 (91.1)	173 (88.3)	0.273	0.095
Metastasis (%)	866 (86.9)	683 (85.3)	183 (93.4)	0.004	0.264
Stage (%)				0.013	0.28
I	70 (7.0)	64 (8.0)	6 (3.1)
II	84 (8.4)	70 (8.7)	14 (7.1)
III	282 (28.3)	234 (29.2)	48 (24.5)
IV	561 (56.3)	433 (54.1)	128 (65.3)
Radiotherapy (%)	301 (30.2)	220 (27.5)	81 (41.3)	<0.001	0.295
Invasive examination (%)	257 (25.8)	199 (24.8)	58 (29.6)	0.204	0.107

Notes: ^†P-value and standardized mean difference (SMD) are established for statistical difference of frailty and non-frailty.

Abbreviations: BMI, body mass index; SD, standardized difference; IQR, interquartile range.

Figure 1 Kaplan–Meier curves displaying survival probability of all-cause mortality according to frail and non-frail patients.

Table 2 Effects of Frailty vs Non-Frailty on All Outcomes

Outcome	Frailty vs Non-Frailty^#
	Model 1^†	Model 2^‡	Model 3^¶
Long-term outcome
All-cause mortality (HR; 95% CI)	1.42 (1.18, 1.70)	1.45 (1.21, 1.75)	1.29 (1.05, 1.60)
Overall survival (Months) (aRMST; 95% CI)	−7.55 (−11.49, −3.62)	−8.02 (−12.02, −4.01)	−5.68 (−10.15, −1.21)
Short-term outcome
Infection (OR; 95% CI)	2.20 (1.35, 3.59)	2.07 (1.25, 3.42)	1.83 (1.09, 3.06)
Bone suppression (OR; 95% CI)	1.65 (1.11, 2.44)	1.64 (1.09, 2.46)	1.54 (1.00, 2.38)
Chemotherapy discontinuation (OR; 95% CI)	2.67 (1.09, 6.56)	2.69 (1.10, 6.61)	1.93 (0.78, 4.82)
Impaired liver function (OR; 95% CI)	1.23 (0.67, 2.25)	1.02 (0.55, 1.90)	1.15 (0.58, 2.28)
Gastrointestinal reactions (OR; 95% CI)	0.95 (0.47, 1.92)	0.90 (0.44, 1.85)	1.24 (0.56, 2.77)
Length of hospitalization (Days) (Median difference; 95% CI)	2.00 (−5.23, 9.64)	2.00 (−6.82, 11.19)	1.00 (−4.71, 11.54)

Notes: ^#Frailty was defined using frailty index ≥0.2; ^†Model 1 was adjusted for age and sex; ^‡Model 2 was further adjusted for smoke, alcohol and BMI; ^¶Model 3 was further adjusted for histology, clinical stage, metastasis, regimen of chemotherapy, radiotherapy, invasive.

Abbreviations: HR, hazard ratio; aRMST, adjusted restricted mean survival time; OR, odds ratio; CI, confidence interval.