Table 1. Open in new tab Baseline...

	Overall Series	Propensity Score–Matched Pairs
Age, mean (SD), y	72.5 (11.3)	72.6 (10.5)	0.009	72.7 (11.1)	72.7 (11.1)	0
Female, No. (%)	183 (3.0)	1247 (4.2)	0.063	134 (3.4)	147 (3.8)	0.018
Race, No. (%)
White	4330 (72.0)	22 704 (76.7)	0.108	2906 (74.5)	2988 (76.6)	0.049
Black	1450 (24.1)	6041 (20.4)	0.089	869 (22.3)	795 (20.4)	0.046
Other	235 (3.9)	850 (2.9)	0.057	128 (3.3)	120 (3.1)	0.012
ICU status, No. (%)	2147 (35.7)	4224 (14.3)	0.511	985 (25.2)	902 (23.1)	0.050
Infection type, No. (%)
COPD exacerbation	649 (10.8)	9234 (31.2)	0.518	556 (14.2)	583 (14.9)	0.020
Community-acquired pneumonia	4852 (80.7)	19 136 (64.7)	0.365	3098 (79.4)	3069 (78.6)	0.018
Hospital-acquired pneumonia	514 (8.5)	1225 (4.1)	0.182	249 (6.4)	251 (6.4)	0.002
Clinical parameters, mean (SD)
Systolic blood pressure, mmHg	141 (22.1)	143 (20.7)	0.098	142 (21.5)	142 (21.1)	0.009
Heart rate, beats per minute	92 (18.2)	90 (16.5)	0.109	92 (17.6)	90 (17.1)	0.063
Respiration rate, breaths per minute	21 (4.4)	20 (3.1)	0.263	21 (3.6)	20 (3.5)	0.056
Temperature, °F	98.6 (1.1)	98.4 (0.8)	0.208	98.5 (1.0)	98.5 (0.9)	0
Laboratory findings
White blood cells, mean (SD), ×10³/mm³	10.5 (6.4)	9.5 (5.3)	0.170	10.2 (5.7)	9.8 (6.1)	0.068
Serum creatinine, mean (SD), mg/dL	1.6 (1.5)	1.3 (1.1)	0.228	1.4 (1.3)	1.4 (1.4)	0
MRSA positive, No. (%)	480 (8.0)	1878 (6.3)	0.063	290 (7.4)	266 (6.8)	0.024
Legionella positive, No. (%)	16 (0.3)	52 (0.2)	0.019	8 (0.2)	8 (0.2)	0
COVID positive, No. (%)	619 (10.3)	327 (1.1)	0.404	135 (3.5)	116 (3.0)	0.028
Comorbidities, No. (%)
Alcohol use disorder	885 (14.7)	5234 (17.7)	0.081	601 (15.4)	607 (15.6)	0.004
Congestive heart failure	2629 (43.7)	12 979 (43.9)	0.003	1705 (43.7)	1683 (43.1)	0.011
COPD	3756 (62.4)	22 486 (76.0)	0.296	2598 (66.6)	2556 (65.5)	0.023
Malignancy	1706 (28.4)	8078 (27.3)	0.024	1142 (29.3)	1180 (30.2)	0.021
Dementia	918 (15.3)	3926 (13.3)	0.057	590 (15.1)	580 (14.9)	0.007
Diabetes	2792 (46.4)	13 133 (44.4)	0.041	1751 (44.9)	1778 (45.6)	0.014
Immunosuppressed	766 (12.7)	2924 (9.9)	0.090	441 (11.3)	460 (11.8)	0.015
Rheumatic disease	228 (3.8)	1012 (3.4)	0.020	140 (3.6)	142 (3.6)	0.003
Risk factors for antibiotic resistance, No. (%)
Wound care	3 (<0.1)	5 (<0.1)	0.018	1 (<0.1)	2 (0.1)	0.013
Dialysis	181 (3.0)	321 (1.1)	0.136	54 (1.4)	78 (2.0)	0.048
Prior admission	1470 (24.4)	8124 (27.5)	0.069	1010 (25.9)	1037 (26.6)	0.016
Admission from long-term care facility	116 (1.9)	387 (1.3)	0.049	59 (1.5)	80 (2.0)	0.041
Antibiotics, No. (%)
Cephalosporin	2635 (43.8)	10 465 (35.4)	0.173	1674 (42.9)	1726 (44.2)	0.027
Beta-lactam/beta-lactamase inhibitor	1997 (33.2)	6858 (23.2)	0.224	1259 (32.3)	1038 (26.6)	0.124
Carbapenem	223 (3.7)	427 (1.4)	0.143	96 (2.5)	121 (3.1)	0.039
Fluoroquinolone	493 (8.2)	3470 (11.7)	0.118	358 (9.2)	326 (8.4)	0.029
Glycopeptide	1460 (24.3)	3085 (10.4)	0.372	700 (17.9)	706 (18.1)	0.004
Macrolide	2040 (33.9)	11 578 (39.1)	0.108	1411 (36.2)	1289 (33.0)	0.066
Tetracycline	738 (12.3)	4093 (13.8)	0.046	480 (12.3)	538 (13.8)	0.044
Other	211 (3.5)	1021 (3.4)	0.003	139 (3.6)	160 (4.1)	0.028
Index for disease severity
Modified APACHE II score, mean (SD)	42.4 (20.2)	39.7 (16.9)	0.145	41.3 (19.3)	41.4 (18.1)	0.005

Overall Series

Propensity Score–Matched Pairs

Procalcitonin-Tested (n = 6015)

Not Tested (n = 29 595)

Standard Difference

Procalcitonin-Tested (n = 3903)

Not Tested (n = 3903)

Standard Difference

Age, mean (SD), y

72.5 (11.3)

72.6 (10.5)

0.009

72.7 (11.1)

Female, No. (%)

183 (3.0)

1247 (4.2)

0.063

134 (3.4)

147 (3.8)

0.018

Race, No. (%)

White

4330 (72.0)

22 704 (76.7)

0.108

2906 (74.5)

2988 (76.6)

0.049

Black

1450 (24.1)

6041 (20.4)

0.089

869 (22.3)

795 (20.4)

0.046

Other

235 (3.9)

850 (2.9)

0.057

128 (3.3)

120 (3.1)

0.012

ICU status, No. (%)

2147 (35.7)

4224 (14.3)

0.511

985 (25.2)

902 (23.1)

0.050

Infection type, No. (%)

COPD exacerbation

649 (10.8)

9234 (31.2)

0.518

556 (14.2)

583 (14.9)

0.020

Community-acquired pneumonia

4852 (80.7)

19 136 (64.7)

0.365

3098 (79.4)

3069 (78.6)

0.018

Hospital-acquired pneumonia

514 (8.5)

1225 (4.1)

0.182

249 (6.4)

251 (6.4)

0.002

Clinical parameters, mean (SD)

Systolic blood pressure, mmHg

141 (22.1)

143 (20.7)

0.098

142 (21.5)

142 (21.1)

0.009

Heart rate, beats per minute

92 (18.2)

90 (16.5)

0.109

92 (17.6)

90 (17.1)

0.063

Respiration rate, breaths per minute

21 (4.4)

20 (3.1)

0.263

21 (3.6)

20 (3.5)

0.056

Temperature, °F

98.6 (1.1)

98.4 (0.8)

0.208

98.5 (1.0)

98.5 (0.9)

Laboratory findings

White blood cells, mean (SD), ×10³/mm³

10.5 (6.4)

9.5 (5.3)

0.170

10.2 (5.7)

9.8 (6.1)

0.068

Serum creatinine, mean (SD), mg/dL

1.6 (1.5)

1.3 (1.1)

0.228

1.4 (1.3)

1.4 (1.4)

MRSA positive, No. (%)

480 (8.0)

1878 (6.3)

0.063

290 (7.4)

266 (6.8)

0.024

Legionella positive, No. (%)

16 (0.3)

52 (0.2)

0.019

8 (0.2)

COVID positive, No. (%)

619 (10.3)

327 (1.1)

0.404

135 (3.5)

116 (3.0)

0.028

Comorbidities, No. (%)

Alcohol use disorder

885 (14.7)

5234 (17.7)

0.081

601 (15.4)

607 (15.6)

0.004

Congestive heart failure

2629 (43.7)

12 979 (43.9)

0.003

1705 (43.7)

1683 (43.1)

0.011

COPD

3756 (62.4)

22 486 (76.0)

0.296

2598 (66.6)

2556 (65.5)

0.023

Malignancy

1706 (28.4)

8078 (27.3)

0.024

1142 (29.3)

1180 (30.2)

0.021

Dementia

918 (15.3)

3926 (13.3)

0.057

590 (15.1)

580 (14.9)

0.007

Diabetes

2792 (46.4)

13 133 (44.4)

0.041

1751 (44.9)

1778 (45.6)

0.014

Immunosuppressed

766 (12.7)

2924 (9.9)

0.090

441 (11.3)

460 (11.8)

0.015

Rheumatic disease

228 (3.8)

1012 (3.4)

0.020

140 (3.6)

142 (3.6)

0.003

Risk factors for antibiotic resistance, No. (%)

Wound care

3 (<0.1)

5 (<0.1)

0.018

1 (<0.1)

2 (0.1)

0.013

Dialysis

181 (3.0)

321 (1.1)

0.136

54 (1.4)

78 (2.0)

0.048

Prior admission

1470 (24.4)

8124 (27.5)

0.069

1010 (25.9)

1037 (26.6)

0.016

Admission from long-term care facility

116 (1.9)

387 (1.3)

0.049

59 (1.5)

80 (2.0)

0.041

Antibiotics, No. (%)

Cephalosporin

2635 (43.8)

10 465 (35.4)

0.173

1674 (42.9)

1726 (44.2)

0.027

Beta-lactam/beta-lactamase inhibitor

1997 (33.2)

6858 (23.2)

0.224

1259 (32.3)

1038 (26.6)

0.124

Carbapenem

223 (3.7)

427 (1.4)

0.143

96 (2.5)

121 (3.1)

0.039

Fluoroquinolone

493 (8.2)

3470 (11.7)

0.118

358 (9.2)

326 (8.4)

0.029

Glycopeptide

1460 (24.3)

3085 (10.4)

0.372

700 (17.9)

706 (18.1)

0.004

Macrolide

2040 (33.9)

11 578 (39.1)

0.108

1411 (36.2)

1289 (33.0)

0.066

Tetracycline

738 (12.3)

4093 (13.8)

0.046

480 (12.3)

538 (13.8)

0.044

Other

211 (3.5)

1021 (3.4)

0.003

139 (3.6)

160 (4.1)

0.028

Index for disease severity

Modified APACHE II score, mean (SD)

42.4 (20.2)

39.7 (16.9)

0.145

41.3 (19.3)

41.4 (18.1)

0.005

	Overall Series	Propensity Score–Matched Pairs
Age, mean (SD), y	72.5 (11.3)	72.6 (10.5)	0.009	72.7 (11.1)	72.7 (11.1)	0
Female, No. (%)	183 (3.0)	1247 (4.2)	0.063	134 (3.4)	147 (3.8)	0.018
Race, No. (%)
White	4330 (72.0)	22 704 (76.7)	0.108	2906 (74.5)	2988 (76.6)	0.049
Black	1450 (24.1)	6041 (20.4)	0.089	869 (22.3)	795 (20.4)	0.046
Other	235 (3.9)	850 (2.9)	0.057	128 (3.3)	120 (3.1)	0.012
ICU status, No. (%)	2147 (35.7)	4224 (14.3)	0.511	985 (25.2)	902 (23.1)	0.050
Infection type, No. (%)
COPD exacerbation	649 (10.8)	9234 (31.2)	0.518	556 (14.2)	583 (14.9)	0.020
Community-acquired pneumonia	4852 (80.7)	19 136 (64.7)	0.365	3098 (79.4)	3069 (78.6)	0.018
Hospital-acquired pneumonia	514 (8.5)	1225 (4.1)	0.182	249 (6.4)	251 (6.4)	0.002
Clinical parameters, mean (SD)
Systolic blood pressure, mmHg	141 (22.1)	143 (20.7)	0.098	142 (21.5)	142 (21.1)	0.009
Heart rate, beats per minute	92 (18.2)	90 (16.5)	0.109	92 (17.6)	90 (17.1)	0.063
Respiration rate, breaths per minute	21 (4.4)	20 (3.1)	0.263	21 (3.6)	20 (3.5)	0.056
Temperature, °F	98.6 (1.1)	98.4 (0.8)	0.208	98.5 (1.0)	98.5 (0.9)	0
Laboratory findings
White blood cells, mean (SD), ×10³/mm³	10.5 (6.4)	9.5 (5.3)	0.170	10.2 (5.7)	9.8 (6.1)	0.068
Serum creatinine, mean (SD), mg/dL	1.6 (1.5)	1.3 (1.1)	0.228	1.4 (1.3)	1.4 (1.4)	0
MRSA positive, No. (%)	480 (8.0)	1878 (6.3)	0.063	290 (7.4)	266 (6.8)	0.024
Legionella positive, No. (%)	16 (0.3)	52 (0.2)	0.019	8 (0.2)	8 (0.2)	0
COVID positive, No. (%)	619 (10.3)	327 (1.1)	0.404	135 (3.5)	116 (3.0)	0.028
Comorbidities, No. (%)
Alcohol use disorder	885 (14.7)	5234 (17.7)	0.081	601 (15.4)	607 (15.6)	0.004
Congestive heart failure	2629 (43.7)	12 979 (43.9)	0.003	1705 (43.7)	1683 (43.1)	0.011
COPD	3756 (62.4)	22 486 (76.0)	0.296	2598 (66.6)	2556 (65.5)	0.023
Malignancy	1706 (28.4)	8078 (27.3)	0.024	1142 (29.3)	1180 (30.2)	0.021
Dementia	918 (15.3)	3926 (13.3)	0.057	590 (15.1)	580 (14.9)	0.007
Diabetes	2792 (46.4)	13 133 (44.4)	0.041	1751 (44.9)	1778 (45.6)	0.014
Immunosuppressed	766 (12.7)	2924 (9.9)	0.090	441 (11.3)	460 (11.8)	0.015
Rheumatic disease	228 (3.8)	1012 (3.4)	0.020	140 (3.6)	142 (3.6)	0.003
Risk factors for antibiotic resistance, No. (%)
Wound care	3 (<0.1)	5 (<0.1)	0.018	1 (<0.1)	2 (0.1)	0.013
Dialysis	181 (3.0)	321 (1.1)	0.136	54 (1.4)	78 (2.0)	0.048
Prior admission	1470 (24.4)	8124 (27.5)	0.069	1010 (25.9)	1037 (26.6)	0.016
Admission from long-term care facility	116 (1.9)	387 (1.3)	0.049	59 (1.5)	80 (2.0)	0.041
Antibiotics, No. (%)
Cephalosporin	2635 (43.8)	10 465 (35.4)	0.173	1674 (42.9)	1726 (44.2)	0.027
Beta-lactam/beta-lactamase inhibitor	1997 (33.2)	6858 (23.2)	0.224	1259 (32.3)	1038 (26.6)	0.124
Carbapenem	223 (3.7)	427 (1.4)	0.143	96 (2.5)	121 (3.1)	0.039
Fluoroquinolone	493 (8.2)	3470 (11.7)	0.118	358 (9.2)	326 (8.4)	0.029
Glycopeptide	1460 (24.3)	3085 (10.4)	0.372	700 (17.9)	706 (18.1)	0.004
Macrolide	2040 (33.9)	11 578 (39.1)	0.108	1411 (36.2)	1289 (33.0)	0.066
Tetracycline	738 (12.3)	4093 (13.8)	0.046	480 (12.3)	538 (13.8)	0.044
Other	211 (3.5)	1021 (3.4)	0.003	139 (3.6)	160 (4.1)	0.028
Index for disease severity
Modified APACHE II score, mean (SD)	42.4 (20.2)	39.7 (16.9)	0.145	41.3 (19.3)	41.4 (18.1)	0.005

Overall Series

Propensity Score–Matched Pairs

Procalcitonin-Tested (n = 6015)

Not Tested (n = 29 595)

Standard Difference

Procalcitonin-Tested (n = 3903)

Not Tested (n = 3903)

Standard Difference

Age, mean (SD), y

72.5 (11.3)

72.6 (10.5)

0.009

72.7 (11.1)

Female, No. (%)

183 (3.0)

1247 (4.2)

0.063

134 (3.4)

147 (3.8)

0.018

Race, No. (%)

White

4330 (72.0)

22 704 (76.7)

0.108

2906 (74.5)

2988 (76.6)

0.049

Black

1450 (24.1)

6041 (20.4)

0.089

869 (22.3)

795 (20.4)

0.046

Other

235 (3.9)

850 (2.9)

0.057

128 (3.3)

120 (3.1)

0.012

ICU status, No. (%)

2147 (35.7)

4224 (14.3)

0.511

985 (25.2)

902 (23.1)

0.050

Infection type, No. (%)

COPD exacerbation

649 (10.8)

9234 (31.2)

0.518

556 (14.2)

583 (14.9)

0.020

Community-acquired pneumonia

4852 (80.7)

19 136 (64.7)

0.365

3098 (79.4)

3069 (78.6)

0.018

Hospital-acquired pneumonia

514 (8.5)

1225 (4.1)

0.182

249 (6.4)

251 (6.4)

0.002

Clinical parameters, mean (SD)

Systolic blood pressure, mmHg

141 (22.1)

143 (20.7)

0.098

142 (21.5)

142 (21.1)

0.009

Heart rate, beats per minute

92 (18.2)

90 (16.5)

0.109

92 (17.6)

90 (17.1)

0.063

Respiration rate, breaths per minute

21 (4.4)

20 (3.1)

0.263

21 (3.6)

20 (3.5)

0.056

Temperature, °F

98.6 (1.1)

98.4 (0.8)

0.208

98.5 (1.0)

98.5 (0.9)

Laboratory findings

White blood cells, mean (SD), ×10³/mm³

10.5 (6.4)

9.5 (5.3)

0.170

10.2 (5.7)

9.8 (6.1)

0.068

Serum creatinine, mean (SD), mg/dL

1.6 (1.5)

1.3 (1.1)

0.228

1.4 (1.3)

1.4 (1.4)

MRSA positive, No. (%)

480 (8.0)

1878 (6.3)

0.063

290 (7.4)

266 (6.8)

0.024

Legionella positive, No. (%)

16 (0.3)

52 (0.2)

0.019

8 (0.2)

COVID positive, No. (%)

619 (10.3)

327 (1.1)

0.404

135 (3.5)

116 (3.0)

0.028

Comorbidities, No. (%)

Alcohol use disorder

885 (14.7)

5234 (17.7)

0.081

601 (15.4)

607 (15.6)

0.004

Congestive heart failure

2629 (43.7)

12 979 (43.9)

0.003

1705 (43.7)

1683 (43.1)

0.011

COPD

3756 (62.4)

22 486 (76.0)

0.296

2598 (66.6)

2556 (65.5)

0.023

Malignancy

1706 (28.4)

8078 (27.3)

0.024

1142 (29.3)

1180 (30.2)

0.021

Dementia

918 (15.3)

3926 (13.3)

0.057

590 (15.1)

580 (14.9)

0.007

Diabetes

2792 (46.4)

13 133 (44.4)

0.041

1751 (44.9)

1778 (45.6)

0.014

Immunosuppressed

766 (12.7)

2924 (9.9)

0.090

441 (11.3)

460 (11.8)

0.015

Rheumatic disease

228 (3.8)

1012 (3.4)

0.020

140 (3.6)

142 (3.6)

0.003

Risk factors for antibiotic resistance, No. (%)

Wound care

3 (<0.1)

5 (<0.1)

0.018

1 (<0.1)

2 (0.1)

0.013

Dialysis

181 (3.0)

321 (1.1)

0.136

54 (1.4)

78 (2.0)

0.048

Prior admission

1470 (24.4)

8124 (27.5)

0.069

1010 (25.9)

1037 (26.6)

0.016

Admission from long-term care facility

116 (1.9)

387 (1.3)

0.049

59 (1.5)

80 (2.0)

0.041

Antibiotics, No. (%)

Cephalosporin

2635 (43.8)

10 465 (35.4)

0.173

1674 (42.9)

1726 (44.2)

0.027

Beta-lactam/beta-lactamase inhibitor

1997 (33.2)

6858 (23.2)

0.224

1259 (32.3)

1038 (26.6)

0.124

Carbapenem

223 (3.7)

427 (1.4)

0.143

96 (2.5)

121 (3.1)

0.039

Fluoroquinolone

493 (8.2)

3470 (11.7)

0.118

358 (9.2)

326 (8.4)

0.029

Glycopeptide

1460 (24.3)

3085 (10.4)

0.372

700 (17.9)

706 (18.1)

0.004

Macrolide

2040 (33.9)

11 578 (39.1)

0.108

1411 (36.2)

1289 (33.0)

0.066

Tetracycline

738 (12.3)

4093 (13.8)

0.046

480 (12.3)

538 (13.8)

0.044

Other

211 (3.5)

1021 (3.4)

0.003

139 (3.6)

160 (4.1)

0.028

Index for disease severity

Modified APACHE II score, mean (SD)

42.4 (20.2)

39.7 (16.9)

0.145

41.3 (19.3)

41.4 (18.1)

0.005

Table 1.

Open in new tab

Baseline Characteristics of Procalcitonin-Tested and Nontested Patients Hospitalized With a Presumed Lower Respiratory Tract Infection at 81 VA Medical Centers, 2018–2021

	Overall Series			Propensity Score–Matched Pairs
	Procalcitonin-Tested (n = 6015)	Not Tested (n = 29 595)	Standard Difference	Procalcitonin-Tested (n = 3903)	Not Tested (n = 3903)	Standard Difference
Age, mean (SD), y	72.5 (11.3)	72.6 (10.5)	0.009	72.7 (11.1)	72.7 (11.1)	0
Female, No. (%)	183 (3.0)	1247 (4.2)	0.063	134 (3.4)	147 (3.8)	0.018
Race, No. (%)
White	4330 (72.0)	22 704 (76.7)	0.108	2906 (74.5)	2988 (76.6)	0.049
Black	1450 (24.1)	6041 (20.4)	0.089	869 (22.3)	795 (20.4)	0.046
Other	235 (3.9)	850 (2.9)	0.057	128 (3.3)	120 (3.1)	0.012
ICU status, No. (%)	2147 (35.7)	4224 (14.3)	0.511	985 (25.2)	902 (23.1)	0.050
Infection type, No. (%)
COPD exacerbation	649 (10.8)	9234 (31.2)	0.518	556 (14.2)	583 (14.9)	0.020
Community-acquired pneumonia	4852 (80.7)	19 136 (64.7)	0.365	3098 (79.4)	3069 (78.6)	0.018
Hospital-acquired pneumonia	514 (8.5)	1225 (4.1)	0.182	249 (6.4)	251 (6.4)	0.002
Clinical parameters, mean (SD)
Systolic blood pressure, mmHg	141 (22.1)	143 (20.7)	0.098	142 (21.5)	142 (21.1)	0.009
Heart rate, beats per minute	92 (18.2)	90 (16.5)	0.109	92 (17.6)	90 (17.1)	0.063
Respiration rate, breaths per minute	21 (4.4)	20 (3.1)	0.263	21 (3.6)	20 (3.5)	0.056
Temperature, °F	98.6 (1.1)	98.4 (0.8)	0.208	98.5 (1.0)	98.5 (0.9)	0
Laboratory findings
White blood cells, mean (SD), ×10³/mm³	10.5 (6.4)	9.5 (5.3)	0.170	10.2 (5.7)	9.8 (6.1)	0.068
Serum creatinine, mean (SD), mg/dL	1.6 (1.5)	1.3 (1.1)	0.228	1.4 (1.3)	1.4 (1.4)	0
MRSA positive, No. (%)	480 (8.0)	1878 (6.3)	0.063	290 (7.4)	266 (6.8)	0.024
Legionella positive, No. (%)	16 (0.3)	52 (0.2)	0.019	8 (0.2)	8 (0.2)	0
COVID positive, No. (%)	619 (10.3)	327 (1.1)	0.404	135 (3.5)	116 (3.0)	0.028
Comorbidities, No. (%)
Alcohol use disorder	885 (14.7)	5234 (17.7)	0.081	601 (15.4)	607 (15.6)	0.004
Congestive heart failure	2629 (43.7)	12 979 (43.9)	0.003	1705 (43.7)	1683 (43.1)	0.011
COPD	3756 (62.4)	22 486 (76.0)	0.296	2598 (66.6)	2556 (65.5)	0.023
Malignancy	1706 (28.4)	8078 (27.3)	0.024	1142 (29.3)	1180 (30.2)	0.021
Dementia	918 (15.3)	3926 (13.3)	0.057	590 (15.1)	580 (14.9)	0.007
Diabetes	2792 (46.4)	13 133 (44.4)	0.041	1751 (44.9)	1778 (45.6)	0.014
Immunosuppressed	766 (12.7)	2924 (9.9)	0.090	441 (11.3)	460 (11.8)	0.015
Rheumatic disease	228 (3.8)	1012 (3.4)	0.020	140 (3.6)	142 (3.6)	0.003
Risk factors for antibiotic resistance, No. (%)
Wound care	3 (<0.1)	5 (<0.1)	0.018	1 (<0.1)	2 (0.1)	0.013
Dialysis	181 (3.0)	321 (1.1)	0.136	54 (1.4)	78 (2.0)	0.048
Prior admission	1470 (24.4)	8124 (27.5)	0.069	1010 (25.9)	1037 (26.6)	0.016
Admission from long-term care facility	116 (1.9)	387 (1.3)	0.049	59 (1.5)	80 (2.0)	0.041
Antibiotics, No. (%)
Cephalosporin	2635 (43.8)	10 465 (35.4)	0.173	1674 (42.9)	1726 (44.2)	0.027
Beta-lactam/beta-lactamase inhibitor	1997 (33.2)	6858 (23.2)	0.224	1259 (32.3)	1038 (26.6)	0.124
Carbapenem	223 (3.7)	427 (1.4)	0.143	96 (2.5)	121 (3.1)	0.039
Fluoroquinolone	493 (8.2)	3470 (11.7)	0.118	358 (9.2)	326 (8.4)	0.029
Glycopeptide	1460 (24.3)	3085 (10.4)	0.372	700 (17.9)	706 (18.1)	0.004
Macrolide	2040 (33.9)	11 578 (39.1)	0.108	1411 (36.2)	1289 (33.0)	0.066
Tetracycline	738 (12.3)	4093 (13.8)	0.046	480 (12.3)	538 (13.8)	0.044
Other	211 (3.5)	1021 (3.4)	0.003	139 (3.6)	160 (4.1)	0.028
Index for disease severity
Modified APACHE II score, mean (SD)	42.4 (20.2)	39.7 (16.9)	0.145	41.3 (19.3)	41.4 (18.1)	0.005

	Overall Series			Propensity Score–Matched Pairs
	Procalcitonin-Tested (n = 6015)	Not Tested (n = 29 595)	Standard Difference	Procalcitonin-Tested (n = 3903)	Not Tested (n = 3903)	Standard Difference
Age, mean (SD), y	72.5 (11.3)	72.6 (10.5)	0.009	72.7 (11.1)	72.7 (11.1)	0
Female, No. (%)	183 (3.0)	1247 (4.2)	0.063	134 (3.4)	147 (3.8)	0.018
Race, No. (%)
White	4330 (72.0)	22 704 (76.7)	0.108	2906 (74.5)	2988 (76.6)	0.049
Black	1450 (24.1)	6041 (20.4)	0.089	869 (22.3)	795 (20.4)	0.046
Other	235 (3.9)	850 (2.9)	0.057	128 (3.3)	120 (3.1)	0.012
ICU status, No. (%)	2147 (35.7)	4224 (14.3)	0.511	985 (25.2)	902 (23.1)	0.050
Infection type, No. (%)
COPD exacerbation	649 (10.8)	9234 (31.2)	0.518	556 (14.2)	583 (14.9)	0.020
Community-acquired pneumonia	4852 (80.7)	19 136 (64.7)	0.365	3098 (79.4)	3069 (78.6)	0.018
Hospital-acquired pneumonia	514 (8.5)	1225 (4.1)	0.182	249 (6.4)	251 (6.4)	0.002
Clinical parameters, mean (SD)
Systolic blood pressure, mmHg	141 (22.1)	143 (20.7)	0.098	142 (21.5)	142 (21.1)	0.009
Heart rate, beats per minute	92 (18.2)	90 (16.5)	0.109	92 (17.6)	90 (17.1)	0.063
Respiration rate, breaths per minute	21 (4.4)	20 (3.1)	0.263	21 (3.6)	20 (3.5)	0.056
Temperature, °F	98.6 (1.1)	98.4 (0.8)	0.208	98.5 (1.0)	98.5 (0.9)	0
Laboratory findings
White blood cells, mean (SD), ×10³/mm³	10.5 (6.4)	9.5 (5.3)	0.170	10.2 (5.7)	9.8 (6.1)	0.068
Serum creatinine, mean (SD), mg/dL	1.6 (1.5)	1.3 (1.1)	0.228	1.4 (1.3)	1.4 (1.4)	0
MRSA positive, No. (%)	480 (8.0)	1878 (6.3)	0.063	290 (7.4)	266 (6.8)	0.024
Legionella positive, No. (%)	16 (0.3)	52 (0.2)	0.019	8 (0.2)	8 (0.2)	0
COVID positive, No. (%)	619 (10.3)	327 (1.1)	0.404	135 (3.5)	116 (3.0)	0.028
Comorbidities, No. (%)
Alcohol use disorder	885 (14.7)	5234 (17.7)	0.081	601 (15.4)	607 (15.6)	0.004
Congestive heart failure	2629 (43.7)	12 979 (43.9)	0.003	1705 (43.7)	1683 (43.1)	0.011
COPD	3756 (62.4)	22 486 (76.0)	0.296	2598 (66.6)	2556 (65.5)	0.023
Malignancy	1706 (28.4)	8078 (27.3)	0.024	1142 (29.3)	1180 (30.2)	0.021
Dementia	918 (15.3)	3926 (13.3)	0.057	590 (15.1)	580 (14.9)	0.007
Diabetes	2792 (46.4)	13 133 (44.4)	0.041	1751 (44.9)	1778 (45.6)	0.014
Immunosuppressed	766 (12.7)	2924 (9.9)	0.090	441 (11.3)	460 (11.8)	0.015
Rheumatic disease	228 (3.8)	1012 (3.4)	0.020	140 (3.6)	142 (3.6)	0.003
Risk factors for antibiotic resistance, No. (%)
Wound care	3 (<0.1)	5 (<0.1)	0.018	1 (<0.1)	2 (0.1)	0.013
Dialysis	181 (3.0)	321 (1.1)	0.136	54 (1.4)	78 (2.0)	0.048
Prior admission	1470 (24.4)	8124 (27.5)	0.069	1010 (25.9)	1037 (26.6)	0.016
Admission from long-term care facility	116 (1.9)	387 (1.3)	0.049	59 (1.5)	80 (2.0)	0.041
Antibiotics, No. (%)
Cephalosporin	2635 (43.8)	10 465 (35.4)	0.173	1674 (42.9)	1726 (44.2)	0.027
Beta-lactam/beta-lactamase inhibitor	1997 (33.2)	6858 (23.2)	0.224	1259 (32.3)	1038 (26.6)	0.124
Carbapenem	223 (3.7)	427 (1.4)	0.143	96 (2.5)	121 (3.1)	0.039
Fluoroquinolone	493 (8.2)	3470 (11.7)	0.118	358 (9.2)	326 (8.4)	0.029
Glycopeptide	1460 (24.3)	3085 (10.4)	0.372	700 (17.9)	706 (18.1)	0.004
Macrolide	2040 (33.9)	11 578 (39.1)	0.108	1411 (36.2)	1289 (33.0)	0.066
Tetracycline	738 (12.3)	4093 (13.8)	0.046	480 (12.3)	538 (13.8)	0.044
Other	211 (3.5)	1021 (3.4)	0.003	139 (3.6)	160 (4.1)	0.028
Index for disease severity
Modified APACHE II score, mean (SD)	42.4 (20.2)	39.7 (16.9)	0.145	41.3 (19.3)	41.4 (18.1)	0.005

Data are presented as mean (SD) or No. (%).

Abbreviations: APACHE, Acute Physiology and Chronic Health Evaluation; ICU, intensive care unit; COPD, chronic obstructive pulmonary disease; MRSA, methicillin-resistant Staphylococcus aureus.

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