Charlson comorbidity index derived from chart review or administrative data: agreement and prediction of mortality in intensive care patients

Figures & data

Table 1 Characteristics of intensive care patients included in the study (n=959) according to complete or incomplete scores

Characteristics	CCI from chart; missing administrative data score (n=120)	CCI score from chart and administrative data (n=839)	p-value
Age in years, mean (SD)	54.2 (18.4)	59.2 (18.1)	0.005
Sex, n (%)			0.703
Women	49 (41)	358 (43)
Men	71 (59)	481 (57)
Diagnostic categories, n (%)			0.228
Respiratory	29 (24)	225 (27)
Cardiovascular	19 (16)	136 (16)
Gastrointestinal	16 (13)	129 (15)
Neurological	17 (14)	81 (10)
Sepsis	6 (5)	66 (8)
Trauma	12 (10)	40 (5)
Metabolic	12(10)	88 (10)
Others	9 (8)	74 (9)
Type of admission, n (%)			0.191
Medical	93 (78)	610 (73)
Unscheduled surgical	25 (21)	184 (22)
Scheduled surgical	2 (2)	45 (5)
Ventilator treatment, n (%)			0.503
Yes	98 (82)	663 (79)
No	22 (18)	176 (21)
In-hospital discharge, n (%)			0.458
Dead	30 (25)	237 (28)
Alive	90 (75)	602 (72)
SAPS II score, mean (SD)	42.3 (17.8)	42.4 (17.1)	0.95
Charlson score (from charts), n (%)			<0.001
0	68 (57)	296 (35)
1	31 (26)	170 (20)
≥2	21 (18)	373 (45)
Time from admission to ICU, days			<0.001
Admission, median (25th–75th percentiles)	0.09 (0.04–0.57)*	0.39 (0.07–3.06)**

Notes:

* n=119;

** n=817.

Abbreviations: CCI, Charlson comorbidity index; ICU, intensive care unit; SAPS, Simplified Acute Physiology Score; SD, standard deviation.

Figure 1 Scatter plot of CCI scores according to source of deriving the score, either from register or chart review.

Note: n=959.
Abbreviation: CCI, Charlson comorbidity index.

Table 2 Spearman’s rank correlations between different variations of Charlson comorbidity scores (n=959)

Correlations	CCI chart (0–33 scale)	CCI chart, 3 categories (0, 1, ≥2)	CCI administrative data, 3 categories (0, 1, ≥2)
Charlson index administrative data (0–29 scale)	0.692	0.668	0.977
Charlson index administrative data, 3 categories (0, 1, ≥2)	0.671	0.662
Charlson index chart, 3 categories (0, 1, ≥2)	0.966

Note: p<0.001 for all correlations.

Abbreviation: CCI, Charlson comorbidity index.

Table 3 Cross-tabulation of categorized Charlson index from the 2 sources

Categories from charts	From administrative data			Sum
	0	1	≥2
0	308	36	20	364
1	88	73	40	201
≥2	60	58	276	394
Sum	456	167	336	959

Notes: McNemar’s test, p<0.001. Data represent number of patients.

Table 4 Prevalence, agreement, and positive predictive value for Charlson score from administrative and chart data (n=959)

Condition	International Classification of Diseases, 10th revision codes	Prevalence, n (%)		Agreement, %	Kappa (95% CI)	Positive predictive value (95% CI)#
		Administrative data	Chart
Myocardial infarction	121, 122, 125.2	140 (15)	171 (18)	90.7	0.66 (0.59–0.72)	79.3 (71.6–85.7)
Congestive heart failure	109.9, 111.0, 113.0, 113.2, 125.5, 142.0, 142.5–142.9, 143, 150, P29.0	79 (8)	96 (10)	90.9	0.45 (0.36–0.55)	55.7 (44.1–66.9)
Peripheral vascular disease	170, 171, 173.1, 173.8, 173.9, 177.1, 179.0, 179.2, K55.1, K55.8, K55.9, Z95.8, Z95.9	90 (9)	106 (11)	90.2	0.47 (0.38–0.56)	56.7 (45.8–67.1)
Cerebrovascular disease	G45, G46, 160–169, H34.0	97 (10)	79 (8)	92.7	0.56 (0.47–0.65)	54.6 (44.2–64.8)
Dementia	F00–F03, G30, F05.1, G31.1	8 (1)	20 (2)	98.3	0.42 (0.19–0.65)	75.0 (34.9–96.8)
Chronic pulmonary disease	127.8, 127.9, J40–J47, J60–J67, J68.4, J70.1, J70.3	171 (18)	214 (22)	88.8	0.65 (0.59–0.71)	81.3 (74.6–86.8)
Rheumatologic disease	M05, M06, M31.5, M32–M34, M35.1, M35.3, M36.0	12 (1)	28 (3)	97.1	0.29 (0.10–0.47)	50.0 (21.1–78.9)
Peptic ulcer	K25–K28	42 (4)	46 (5)	94.0	0.31 (0.18–0.44)	35.7 (21.6–52.0)
Hemiplegia/paraplegia	G04.1, G11.4, G80.1, G80.2, G81, G82, G83.0, G83.1, G83.2, G83.3, G83.4, G83.9	10 (1)	27 (3)	97.4	0.31 (0.12–0.51)	60.0 (26.2–87.8)
Diabetes without complications	E10.0, E10.1, E10.6, E10.8, E10.9, E11.0, E11.1, E11.6, E11.8, E11.9, E12.0, E12.1, E12.6, E12.8, E12.9, E13.0, E13.1, E13.6, E13.8, E13.9, E14.0, E14.1, E14.6, E14.8, E14.9	101 (11)	92 (10)	92.8	0.60 (0.52–0.69)	61.4 (51.2–70.9)
Diabetes with chronic complications	E10.2–E10.5, E10.7, E11.2–E11.5, E11.7, E12.2–E12.5, E12.7, E13.2–E13.5, E13.7, E14.2–E14.5, E14.7	30 (3)	34 (4)	96.2	0.42 (0.26–0.57)	46.7 (28.3–65.7)
Mild liver disease	B18, K70.0–K70.3, K70.9, K71.3–K71.5, K71.7, K73, K74, K76.0, K76.2–K76.4, K76.8, K76.9, Z94.4	37 (4)	31 (3)	96.0	0.42 (0.27–0.57)	40.5 (24.8–57.9)
Moderate/severe liver disease	185.0, 185.9, 186.4, 198.2, K70.4, K71.1, K72.1, K72.9, K76.5–K76.7	6 (1)	9 (1)	98.9	0.26 (−0.04–0.56)	33.3 (4.3–77.7)
Renal disease	112.0, 113.1, N03.2–N03.7, N05.2–N05.7, N18, N19, N25.0, Z49.0–Z49.2, Z94.0, Z99.2	57 (6)	53 (6)	95.6	0.60 (0.48–0.71)	59.6 (45.8–72.4)
Any malignancy (tumor, leukemia, lymphoma)	C00–C26, C30–C34, C37–C41, C43, C45–C58, C60–C76, C81–C85, C88, C90–C97	144 (15)	79 (8)	89.5	0.49 (0.41–0.58)	42.4 (34.2–50.9)
Metastatic solid tumor	C77–C80	16 (2)	30 (3)	97.9	0.56 (0.38–0.73)	81.3 (54.4–96.0)
HIV/AIDS	B20–B22, B24	0 (0)	4 (0.4)	99.6	–	–

Note:

# Using chart review as the reference.

Abbreviations: AIDS, acquired immune deficiency syndrome; CI, confidence interval; HIV, human immunodeficiency virus.

Table 5 Discrimination for the risk-adjustment models according to included variables, using c-statistics (area under the ROC curve) with 95% CI for 30-day and 1-year mortality

Variables/models	30-day mortality	1-year mortality
Crude mortality, n (%)	249 (26.0)	341 (35.6)
Chart reviewa
Charlson score	0.656 (0.621–0.692)	0.681 (0.649–0.714)
Charlson score, age, sex	0.743 (0.710 – 0.775)	0.772 (0.743–0.802)
Charlson score, age, sex, type of admission	0.755 (0.723–0.788)	0.783 (0.753–0.812)
Charlson score, age, sex, type of admission, ventilator	0.773 (0.742–0.804)	0.792 (0.763–0.820)
Register-basedb
Charlson score	0.607 (0.570–0.644)	0.664 (0.630–0.697)
Charlson score, age, sex	0.734 (0.701–0.768)	0.764 (0.734–0.794)
Charlson score, age, sex, type of admission	0.743 (0.709–0.777)	0.775 (0.745–0.805)
Charlson score, age, sex, type of admission, ventilator	0.762 (0.729–0.794)	0.783 (0.754–0.813)
Physiology-baseda
SAPS II	0.821 (0.792–0.850)	0.790 (0.761–0.819)
SAPS II, Charlson score	0.834 (0.806–0.861)	0.816 (0.789–0.843)
SAPS II, Charlson score, age	0.849 (0.822–0.875)	0.838 (0.813–0.864)

Notes: Charlson score categorized as 0, 1, ≥2. All patients (n=959).

a Charlson score from chart review.

b Including replacement of 0 for missing Charlson score from register.

Abbreviations: CI, confidence interval; ROC, receiver-operator characteristic; SAPS, Simplified Acute Physiology Score.

Table 6 Model calibration for various combinations of covariates

Model	30-day mortality	p-value	1-year mortality	p-value
	Hosmer–Lemeshow goodness of fit		Hosmer–Lemeshow goodness of fit
Chart review
Charlson score	n/a		n/a
Charlson score, age, sex	14.79	0.063	11.12	0.195
Charlson score, age, sex, type of admission	9.69	0.287	14.44	0.071
Charlson score, age, sex, type of admission, ventilator	7.42	0.492	4.22	0.836
Register-baseda
Charlson score	n/a		n/a
Charlson score, age, sex	10.42	0.236	9.13	0.331
Charlson score, age, sex, type of admission	4.76	0.783	9.54	0.299
Charlson score 3, age, sex, type of admission, ventilator	2.45	0.964	4.48	0.812
Physiology-based
SAPS II	5.81	0.669	7.36	0.498
SAPS II, Charlson score (chart review)	18.01	0.021	10.22	0.250
SAPS II, Charlson (chart review), age	10.94	0.205	14.99	0.059

Notes: Charlson score categorized as 0, 1, ≥2 (n=959). n/a, not applicable because only 3 categories are present.

a Including replacement of 0 for missing Charlson score from register.

Abbreviation: SAPS, Simplified Acute Physiology Score.