Table 1.
Patient Baseline Characteristics, before and after Inverse Probability of Treatment Weighting (IPTW)
| Before IPTW | Standardized Difference | After IPTW | Standardized Difference | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||
| Cancer Group
|
Non-cancer Group
|
Cancer Group
|
Non-cancer Group
|
|||||||
| N=1,142 | N=1,142 | N=1,142 | N=1,142 | |||||||
| Mean | STDa | Mean | STDa | Mean | STDa | Mean | STDa | |||
|
|
|
|
|
|||||||
| Age, yr | 75.6 | (6.7) | 75.6 | (6.7) | 0.000b | 75.6 | (6.7) | 75.6 | (6.7) | 0.000c |
| Klabunde Comorbidity Score | 1.0 | (1.3) | 1.2 | (1.4) | −0.106 | 1.1 | (1.9) | 1.1 | (2.0) | −0.041 |
| Proportion of Days Covered (PDC) | 0.71 | (0.33) | 0.71 | (0.33) | 0.005 | 0.71 | (0.47) | 0.70 | (0.47) | 0.007 |
| Numbers of Office Visit | 9.5 | (8.1) | 9.1 | (8.0) | 0.054 | 9.5 | (11.4) | 9.2 | (11.2) | 0.029 |
| N | % | N | % | Nd | % | Nd | % | |||
|
|
|
|
|
|||||||
| Race/Ethnicity | 0.054 | 0.029 | ||||||||
| White | 1,026 | (89.8) | 980 | (85.8) | 1,018 | (89.2) | 992 | (86.9) | ||
| Black | 61 | (5.3) | 66 | (5.8) | 65 | (5.7) | 61 | (5.4) | ||
| Others | 33 | (2.9) | 55 | (4.8) | 24 | (3.1) | 38 | (4.5) | ||
| Hispanic | 22 | (1.9) | 41 | (3.6) | 35 | (2.1) | 51 | (3.3) | ||
| LISe/Dual Eligibility | −0.189 | 0.000c | ||||||||
| Any Extra helpf | 489 | (42.8) | 596 | (52.2) | 543 | (47.5) | 543 | (47.5) | ||
| No Extra helpf | 653 | (57.2) | 546 | (47.8) | 600 | (52.5) | 600 | (52.5) | ||
| Klabunde Comorbidity Score33 | −0.189 | 0.000c | ||||||||
| 0 | 527 | (46.2) | 474 | (41.5) | 513 | (45.0) | 486 | (42.6) | ||
| 1 | 317 | (27.8) | 324 | (28.4) | 318 | (27.9) | 323 | (28.3) | ||
| 2 | 150 | (13.1) | 176 | (15.4) | 156 | (13.7) | 171 | (15.0) | ||
| 3+ | 148 | (13.0) | 168 | (14.7) | 154 | (13.5) | 161 | (14.1) | ||
| Proportion of Days Covered (PDC) | −0.189 | 0.000c | ||||||||
| 0.8 ≤ PDC | 636 | (58.1) | 663 | (55.7) | 664 | (58.1) | 634 | (55.5) | ||
| 0.6 le; PDC < 0.8 | 183 | (12.8) | 146 | (16.0) | 147 | (12.9) | 184 | (16.1) | ||
| 0.4 le; PDC < 0.6 | 102 | (8.6) | 98 | (8.9) | 96 | (8.4) | 104 | (9.1) | ||
| 0.2le; PDC < 0.4 | 56 | (6.7) | 77 | (4.9) | 77 | (6.7) | 56 | (4.9) | ||
| PDC< 0.2 | 165 | (13.9) | 158 | (14.5) | 158 | (13.8) | 164 | (14.4) | ||
| Long Last Refill before Pre-Index Date Period | 187 | (16.3) | 195 | (17.1) | 0.019 | 187 | (16.4) | 198 | (17.3) | −0.025 |
| Last Drug Class Used before Pre-Index Date Period | 0.019 | −0.025 | ||||||||
| SSRIs | 701 | (61.4) | 694 | (60.8) | 703 | (61.6) | 695 | (60.9) | ||
| SNRIs | 192 | (16.8) | 168 | (14.7) | 191 | (16.8) | 168 | (14.7) | ||
| TCAs | 81 | (7.1) | 78 | (6.8) | 81 | (7.1) | 78 | (6.8) | ||
| Others | 168 | (14.7) | 202 | (17.7) | 166 | (14.5) | 202 | (17.7) | ||
| Index Year | 0.000b | 0.000c | ||||||||
| 2008 | 181 | (15.9) | 181 | (15.9) | 182 | (15.9) | 181 | (15.8) | ||
| 2009 | 322 | (28.2) | 322 | (28.2) | 323 | (28.2) | 321 | (28.1) | ||
| 2010 | 319 | (27.9) | 319 | (27.9) | 317 | (27.9) | 319 | (27.9) | ||
| 2011 | 320 | (28.0) | 320 | (28.0) | 320 | (28.0) | 322 | (28.2) | ||
| Cancer Stage | ||||||||||
| I | 567 | (49.7) | ||||||||
| II | 406 | (35.6) | ||||||||
| III | 126 | (11.0) | ||||||||
| IV | 43 | (3.8) | ||||||||
| Cancer Grade | ||||||||||
| Well differentiated | 281 | (24.6) | ||||||||
| Moderately differentiated | 495 | (43.3) | ||||||||
| Poorly differentiated | 294 | (25.8) | ||||||||
| Undetermined | 72 | (6.3) | ||||||||
| Number of positive lymph nodes | ||||||||||
| 0 | 663 | (58.1) | ||||||||
| 1–4 | 201 | (17.6) | ||||||||
| 5+ | 78 | (6.8) | ||||||||
| Unknown | 200 | (17.5) | ||||||||
| Estrogen receptors | ||||||||||
| Positive/Borderline | 930 | (81.4) | ||||||||
| Negative | 158 | (13.8) | ||||||||
| Unknown | 54 | (4.7) | ||||||||
| Progesterone receptor | ||||||||||
| Positive/Borderline | 790 | (69.2) | ||||||||
| Negative | 298 | (26.1) | ||||||||
| Unknown | 54 | (4.7) | ||||||||
a
STD, standard deviation
b
Age and index year were matching variables before applying IPTW, thus the standardized difference is zero.
c
The standardized difference is less than 0.001.
d
The weighted values were rounded to the nearest whole number as whole person.
e
LIS, Low income subsidy.
f
Extra help was defined as qualified for full LIS, partial LIS, or Medicare Dual-eligible beneficiaries at the month of index date.