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. 2021 Aug 20;4(8):e2120951. doi: 10.1001/jamanetworkopen.2021.20951

Table 2. Univariable Logistic Regression: Association of Selected Factors With Receipt of RT .

Factor Age 18-39 y (n = 1280) Age 40-64 y (n = 3937) Age ≥65 y (n = 3736) All (N = 8953)
OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value
Sex
Male 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Female 0.78 (0.62-0.97) .03 1.05 (0.91-1.20) .52 0.92 (0.80-1.05) .21 0.93 (0.86-1.02) .12
Race/ethnicity
White Non-Hispanic 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
White Hispanic 0.50 (0.36-0.70) .001 0.80 (0.61-1.05) .10 0.77 (0.54-1.10) .15 0.69 (0.58-0.83) .001
Black 0.74 (0.54-1.02) .07 0.90 (0.73-1.11) .34 1.07 (0.82-1.39) .64 0.93 (0.80-1.07) .30
Other or unknowna 0.72 (0.50-1.04) .08 0.89 (0.70-1.12) .32 1.03 (0.82-1.30) .79 0.91 (0.78-1.05) .21
Insurance status
Not insured 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Private insurance 2.10 (1.44-3.06) <.001 1.54 (1.17-2.04) .002 2.45 (1.02-5.91) .045 1.83 (1.48-2.27) .001
Medicaid 1.28 (0.82-2.01) .28 1.21 (0.84-1.74) .31 1.70 (0.62-4.67) .30 1.21 (0.92-1.58) .17
Medicare 1.37 (0.66-2.83) .40 0.97 (0.67-1.39) .85 1.83 (0.77-4.32) .17 1.35 (1.09-1.67) .006
Other or unknown 2.82 (1.37-5.79) .005 1.32 (0.86-2.04) .20 3.36 (1.23-9.13) .02 1.92 (1.38-2.67) <.001
Median income in patient’s zip code in 2012, $
<38 000 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
48 000-62 999 1.02 (0.76-1.37) .90 0.91 (0.76-1.09) .32 0.92 (0.77-1.10) .35 0.92 (0.82-1.03) .17
38 000-47 999 0.76 (0.56-1.04) .09 0.93 (0.77-1.12) .44 0.88 (0.73-1.06) .17 0.88 (0.78-0.99) .03
≥63 000 0.58 (0.42-0.81) .001 0.82 (0.67-1.00) .045 0.76 (0.62-0.93) .008 0.74 (0.65-0.85) .001
Unknown 1.08 (0.39-2.98) .88 1.02 (0.58-1.78) .95 0.57 (0.34-0.95) .03 0.78 (0.55-1.10) .16
Non–high school graduates, % of population in patient’s zip code
<7 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
7-12.9 1.17 (0.86-1.59) .32 0.91 (0.76-1.08) .28 0.89 (0.74-1.06) .18 0.93 (0.83-1.04) .20
13-20.9 0.99 (0.72-1.38) .97 0.92 (0.76-1.12) .43 0.88 (0.73-1.06) .18 0.91 (0.80-1.03) .12
≥21 0.70 (0.50-0.98) .04 0.79 (0.65-0.98) .03 0.75 (0.60-0.93) .01 0.76 (0.66-0.87) .001
Unknown 1.21 (0.40-3.70) .74 1.04 (0.56-1.91) .91 0.56 (0.34-0.95) .03 0.78 (0.54-1.12) .18
Living location
Metropolitanb 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Smaller metropolitanb 0.87 (0.67-1.12) .28 0.85 (0.73-0.99) .04 1.05 (0.90-1.22) .57 0.92 (0.84-1.02) .12
Urban 0.79 (0.56-1.12) .19 0.85 (0.70-1.04) .11 1.15 (0.95-1.41) .16 0.96 (0.84-1.09) .54s
Rural 0.53 (0.16-1.76) .30 0.80 (0.47-1.35) .40 0.98 (0.59-1.65) .95 0.86 (0.61-1.22) .39
Unknown 1.18 (0.61-2.31) .62 1.19 (0.80-1.78) .38 0.76 (0.54-1.06) .11 0.94 (0.74-1.19) .62
Distance to reporting facility, miles
≤10 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
11-20 0.74 (0.54-1.03) .08 0.81 (0.67-0.99) .04 0.86 (0.71-1.05) .14 0.83 (0.73-0.94) .004
21-50 0.82 (0.60-1.14) .24 0.71 (0.59-0.86) <.001 0.98 (0.81-1.18) .82 0.84 (0.74-0.95) .005
>50 0.57 (0.43-0.76) <.001 0.50 (0.42-0.60) .001 0.66 (0.56-0.79) .001 0.58 (0.52-0.65) .001
Unknown 0.85 (0.27-2.64) .78 0.81 (0.45-1.48) .50 0.57 (0.34-0.97) .04 0.69 (0.48-1.00) .05
Comorbidities, No.
0 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
1 1.14 (0.67-1.93) .63 0.82 (0.67-1.00) .05 0.78 (0.66-0.92) .003 0.82 (0.72-0.92) <.001
2 0.46 (0.08-2.76) .40 0.64 (0.42-0.98) .04 0.73 (0.54-0.98) .04 0.70 (0.55-0.89) .003
Transition in care
No 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Yes 1.30 (0.95-1.78) .10 1.26 (1.04-1.54) .02 1.67 (1.38-2.01) .001 1.44 (1.27-1.63) .001
Unknown 0.91 (0.65-1.28) .59 1.09 (0.88-1.35) .42 1.19 (0.98-1.46) .09 1.11 (0.97-1.27) .12
Primary site
Upper limb 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Lower limb 1.09 (0.85-1.41) .48 1.06 (0.90-1.24) .49 0.91 (0.78-1.06) .23 1.01 (0.91-1.12) .84
Grade
MD 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
PD 1.08 (0.80-1.47) .62 1.17 (0.96-1.44) .12 1.21 (0.97-1.51) .10 1.16 (1.02-1.33) .03
UD 0.92 (0.66-1.28) .62 1.19 (0.96-1.48) .11 1.28 (1.01-1.61) .04 1.18 (1.02-1.36) .02
Tumor size, cm
≤5.00 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
5.01-10.00 1.70 (1.30-2.22) <.001 1.84 (1.56-2.18) .001 1.47 (1.25-1.73) .001 1.64 (1.48-1.83) .001
10.01-15.00 1.92 (1.38-2.67) <.001 1.77 (1.45-2.16) .001 1.71 (1.40-2.09) .001 1.78 (1.56-2.02) .001
>15.00 1.36 (0.93-1.99) .11 1.53 (1.25-1.88) .001 1.29 (1.04-1.59) .02 1.43 (1.25-1.64) .001
Clinical tumor stage
I 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
II 1.63 (1.24-2.14) <.001 1.99 (1.69-2.36) .001 1.60 (1.35-1.89) .001 1.76 (1.58-1.97) .001
Unknown 1.27 (0.92-1.77) .152 1.43 (1.17-1.74) <.001 1.15 (0.95-1.40) .16 1.29 (1.13-1.46) <.001
Depth of extension
Superficial 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Deep 1.85 (1.42-2.42) .001 1.64 (1.40-1.91) .001 1.30 (1.12-1.51) <.001 1.51 (1.37-1.67) .001
Unknown 1.20 (0.80-1.82) .38 1.07 (0.83-1.39) .59 0.97 (0.74-1.25) .79 1.03 (0.87-1.22) .72
Surgical margin
Negative 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA 1 [Reference] NA
Positive 1.33 (0.89-2.01) .17 1.33 (1.06-1.65) .01 1.26 (1.05-1.50) .01 1.27 (1.12-1.45) <.001
Unknown 0.75 (0.43-1.29) .30 1.39 (0.93-2.07) .11 1.22 (0.86-1.73) .26 1.15 (0.91-1.45) .24
Age, y
18-39 NA NA NA NA NA NA 1 [Reference] NA
40-64 NA NA NA NA NA NA 1.53 (1.35-1.75) .001
≥65 NA NA NA NA NA NA 1.19 (1.04-1.35) .009

Abbreviations: MD, moderately differentiated; NA, not applicable; OR, odds ratio; PD, poorly differentiated; RT, radiation therapy; UD, undifferentiated.

a

Other races/ethnicities included American Indian, Aleutian, or Eskimo; Chinese; Japanese; Filipino; Hawaiian; Korean; Vietnamese; Laotian; Hmong; Kampuchean; Thai; Asian Indian or Pakistani, not otherwise specified; Asian Indian; Pakistani; Micronesian, not otherwise specified; Chamorran; Guamanian, not otherwise specified; Polynesian, not otherwise specified; Tahitian, Samoan, Tongan, Melanesian, not otherwise specified; Fiji Islander; New Guinean; other Asian, including Asian, not otherwise specified, and Oriental, not otherwise specified; and Pacific Islander, not otherwise specified.

b

Metropolitan was defined as having a population of 250 000 or greater; smaller metropolitan, 20 000 to less than 250 000.