Validation of Fill-In Algorithm for Ascertainment of Nursing Facility Stays

APPENDIX

Validation of “fill-in” algorithm for ascertainment of nursing facility stays

We first developed the “fill-in” algorithm to compute nursing facility days for the USRDS 2016 Annual Data Report1. To identify days spent in a nursing facility, we used Medicare Part A and Part B claims. Part A covers only the first 100 days of skilled nursing facility care after a qualifying hospital stay, and therefore may underestimate the total days in a nursing facility. We therefore used the place of service from Part B billing claims to identify additional days spent in a skilled nursing facility, hospice facility, assisted living facility, intermediate care facility, or custodial care facility (Appendix Table 1). Given the intermittent nature of Part B claims (which are generally for physician or laboratory services), we made the following assumptions: days between two consecutive Part B nursing facility claims (and without any other claims during that time) were categorized as nursing facility days (up to a maximum of 90 days); days between a Part B nursing facility claim and a hospitalization claim or death were categorized as nursing facility days (up to a maximum of 31 days). We defined patients as being at home if they had a Part A billing claim for home health services, or a Part B claim with “home” as the place of service, or an absence of any other nursing facility billing claims.

To validate this algorithm, we used data from the Minimum Data Set (MDS), a national registry of all patients residing in a Medicare or Medicaid certified nursing facility between 2000 and 2010. The MDS is considered the “gold standard” for determination of nursing facility length of stay2,3. We selected all adult patients with ESRD in the USRDS who died between 2000-2010 and with continuous Medicare parts A&B in the last year of life. We then compared the median number of nursing facility days in the last year of life using the MDS with the median number of nursing facility days computed usingthe fill-in algorithm as described in our manuscript (page 6). Appendix Table 2 shows the median (IQR) of the total number of days, by method used. Overall, the median number of days is very similar between the two methods with the ‘fill-in’ underestimating nursing facility stays by a median of 3 days.

Appendix Table 1: Medicare Part A and B codes used to define patient location
Location / Code
Hospitalization / Part A HCFASAF = I / Inpatient
Part A HCFASAF = M / PMMIS inpat stay
Skilled nursing facility / Part A HCFASAF = N / SNF
Part A HCFASAF = S / Hospice
Part B POS = 31, 32, 61 / SNF
Part B POS = 13 / Assisted living facility
Part B POS = 54 / Intermediate Care
Part B POS = 33 / Custodial Care Facility
Part B POS = 34 / Hospice
Home / Part A HCFASAF = H / HHA
Part B POS = 12 / Home
Absence of any other claims

POS = place of service

Appendix Table 2: Median (25th,75th percentile) total number of nursing facility days by data source.
Year / MDS / Fill-in method
2000 / 46 (16,123) / 43 (14,144)
2001 / 50 (18,146) / 45 (15,149)
2002 / 53 (19,144) / 49 (16,159)
2003 / 53 (19,136) / 51 (17,160)
2004 / 54 (19,133) / 51 (16,159)
2005 / 56 (20,129) / 56 (18,172)
2006 / 57 (20,136) / 54 (18,156)
2007 / 63 (22,166) / 57 (19,163)
2008 / 64 (22,170) / 57 (19,164)
2009 / 65 (22,169) / 59 (20,174)
2010 / 59 (21,145) / 56 (19,160)
Total / 57 (20,154) / 54 (18,162)
Appendix Table 3: ICD-9 codes used to identify comorbid conditions
Comorbidity / ICD-9 Codes
Cardiovascular
Coronary artery disease / 410.x, 412, 36.1x, 414.0x, V45.81, 00.66, 36.0x, v45.82
Heart failure / 398.91, 402.01, 402.11, 402.91, 404.01, 404.03, 404.13, 404.91, 428.x,
Atrial fibrillation / 427.3x
Other arrhythmia / 426.x, 427.0, 427.20, 427.81, 427.9, 427.1, 427.4x, 37.9x, 996.04, v53.32
Stroke / Transient Ischemic Attack / 433.x, 434.x, 435.x , 436.00
Valvular disease / 394.x-397.1, 424.x, 746.3-746.6, v42.2, v43.3
Peripheral artery disease / 38.03, 38.04, 38.05, 38.08, 38.33-38.48, 39.22-39.29, 440.2x, 440.3x, 440.4x, 441.x, 443.x, 445.x, 447.10, 557.10, 557.90, v43.4,
Hypertension / 401.0, 401.1, 401.9, 402.x, 403.x, 404.x, 405.x
Other Medical
Diabetes mellitus / 249.x, 250.x, 357.2, 362.0x
Chronic liver disease / 070.x, 456.1, 456.21, 570-573.x, v42.7
Chronic lung disease / 490, 491.x-496, 500-505, 506.4, 516.x
Dementia / 290.x, 294.1x, 331.x
Depression / 296.2x, 296.3x, 296.5x, 296.82, 300.40, 301.12, 309.0, 309.10, 311
Systemic cancer / 140.x-165.x, 170.x-172.x, 174.x, 175.x, 180.x-209.x, 238.6, 273.3
Appendix Table 4A: For patients age 67-70 years, facility days overall and by survival status at 1 year post-dialysis initiation
Group A: ≥1 facility day in the year post-dialysis initiation / Group B:
Died within 1 year post-dialysis initiation / Group C: Patients from Group B with ≥1 facility day in the year post-dialysis initiation / Group D: Survived to 1 year post-dialysis initiation / Group E: Patients from Group D with ≥1 facility day in the year post-dialysis initiation
Subgroup / Total N / % of total N / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group B / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group D / Mean N(CI) facility days / Mean % (CI) of days spent in a facility
Overall / 5618 / 83.4 / 60 (57, 62) / 25.8 (24.9, 26.7) / 23.9 / 96.1 / 70 (66, 74) / 52.9 (51.0, 54.8) / 76.1 / 79.4 / 56 (52, 59) / 15.5 (14.6, 16.3)
Male / 3006 / 82.3 / 58 (54, 61) / 25.4 (24.1, 26.7) / 24.6 / 95.3 / 66 (61, 71) / 51.1 (48.5, 53.6) / 75.4 / 78.1 / 54 (50, 59) / 15.2 (14.0, 16.4)
Female / 2612 / 84.7 / 62 (58, 65) / 26.2 (24.9, 27.6) / 23.1 / 97.2 / 75 (70, 81) / 55.2 (52.4, 58.0) / 76.9 / 80.9 / 57 (52, 61) / 15.8 (14.5, 17.0)
Non-Black / 4315 / 83.0 / 57 (55, 60) / 25.6 (24.6, 26.7) / 25.2 / 96.0 / 69 (65, 73) / 52.2 (50.1, 54.3) / 74.8 / 78.7 / 53 (49, 56) / 14.7 (13.7, 15.6)
Black / 1303 / 84.7 / 67 (61, 72) / 26.4 (24.4, 28.4) / 19.6 / 96.9 / 77 (68, 85) / 55.9 (51.6, 60.3) / 80.4 / 81.7 / 64 (57, 71) / 17.8 (15.9, 19.8)
-Diabetes / 1593 / 76.8 / 49 (45, 54) / 22.9 (21.2, 24.6) / 23.8 / 92.9 / 59 (53, 66) / 48.4 (44.8, 52.0) / 76.2 / 71.8 / 45 (40, 51) / 12.6 (11.2, 14.1)
+Diabetes / 4025 / 86.0 / 63 (60, 66) / 26.8 (25.7, 27.9) / 24.0 / 97.4 / 74 (70, 79) / 54.6 (52.4, 56.9) / 76.0 / 82.4 / 59 (55, 63) / 16.5 (15.4, 17.5)
-CV disease / 1313 / 67.1 / 39 (35, 44) / 16.4 (14.7, 18.2) / 14.9 / 88.2 / 60 (50, 70) / 44.2 (39.3, 49.1) / 85.1 / 63.4 / 35 (29, 40) / 9.7 (8.3, 11.1)
+CV disease / 4305 / 88.4 / 64 (61, 67) / 28.0 (26.9, 29.0) / 26.7 / 97.5 / 72 (68, 76) / 54.3 (52.2, 56.3) / 73.3 / 85.1 / 61 (57, 65) / 17.0 (16.0, 18.0)
-Dementia / 5338 / 82.8 / 55 (52, 57) / 24.0 (23.0, 24.9) / 23.3 / 95.9 / 67 (64, 71) / 51.0 (49.1, 53.0) / 76.7 / 78.8 / 50 (47, 53) / 14.0 (13.2, 14.8)
+Dementia / 280 / 95.4 / 140 (124, 155) / 56.1 (51.4, 60.8) / 35.7 / 99.0 / 103 (87, 118) / 75.8 (70.0, 81.5) / 64.3 / 93.3 / 161 (139, 184) / 44.5 (38.4, 50.6)
-Depression / 4530 / 81.3 / 51 (49, 54) / 22.1 (21.2, 23.1) / 21.7 / 95.7 / 65 (60, 69) / 48.7 (46.5, 50.9) / 78.3 / 77.3 / 46 (43, 49) / 13.0 (12.2, 13.9)
+Depression / 1088 / 92.4 / 91 (84, 97) / 39.2 (36.9, 41.6) / 33.3 / 97.2 / 85 (78, 92) / 64.3 (60.8, 67.8) / 66.7 / 89.9 / 94 (85, 103) / 25.8 (23.3, 28.3)
Appendix Table 4B: For patients age 71-75 years, facility days overall and by survival status at 1 year post-dialysis initiation
Group A: ≥1 facility day in the year post-dialysis initiation / Group B:
Died within 1 year post-dialysis initiation / Group C: Patients from Group B with ≥1 facility day in the year post-dialysis initiation / Group D: Survived to 1 year post-dialysis initiation / Group E: Patients from Group D with ≥1 facility day in the year post-dialysis initiation
Subgroup / Total N / % of total N / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group B / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group D / Mean N(CI) facility days / Mean % (CI) of days spent in a facility
Overall / 7052 / 84.7 / 59 (57, 61) / 27.1 (26.3, 28.0) / 28.1 / 96.5 / 67 (64, 70) / 52.3 (50.7, 53.9) / 71.9 / 80.1 / 55 (52, 57) / 15.3 (14.5, 16.0)
Male / 3873 / 82.9 / 53 (50, 55) / 24.8 (23.7, 26.0) / 27.2 / 85.6 / 61 (57, 65) / 49.1 (47.0, 51.3) / 72.8 / 78.1 / 49 (45, 52) / 13.7 (12.8, 14.7)
Female / 3179 / 86.9 / 66 (62, 69) / 29.8 (28.5, 31.1) / 29.1 / 97.5 / 74 (69, 78) / 55.9 (53.6, 58.2) / 70.9 / 82.6 / 62 (57, 66) / 17.1 (15.9, 18.3)
Non-Black / 5624 / 84.4 / 56 (54, 58) / 26.5 (25.5, 27.4) / 29.1 / 96.0 / 64 (61, 67) / 50.6 (48.8, 52.3) / 70.9 / 79.7 / 52 (49, 55) / 14.5 (13.7, 15.4)
Black / 1428 / 85.8 / 69 (63, 74) / 29.6 (27.7, 31.6) / 24.1 / 98.8 / 81 (73, 89) / 60.4 (56.6, 64.2) / 75.9 / 81.6 / 64 (57, 70) / 17.8 (16.0, 19.6)
-Diabetes / 2191 / 79.1 / 48 (45, 52) / 24.1 (22.6, 25.5) / 27.7 / 94.6 / 60 (55, 65) / 48.3 (45.5, 51.1) / 72.3 / 73.1 / 43 (38, 47) / 12.1 (10.9, 13.3)
+Diabetes / 4861 / 87.2 / 63 (60, 65) / 28.4 (27.3, 29.4) / 28.3 / 97.4 / 70 (66, 73) / 54.1 (52.1, 56.0) / 71.7 / 83.3 / 60 (56, 63) / 16.5 (15.6, 17.5)
-CV disease / 1425 / 67.4 / 38 (34, 42) / 15.8 (14.2, 17.4) / 15.8 / 88.4 / 49 (41, 56) / 38.0 (33.4, 42.7) / 84.2 / 63.5 / 35 (30, 40) / 10.0 (8.6, 11.3)
+CV disease / 5627 / 89.1 / 63 (60, 65) / 29.3 (28.3, 30.2) / 31.2 / 97.5 / 69 (66, 72) / 54.0 (52.3, 55.7) / 68.8 / 85.2 / 59 (56, 62) / 16.5 (15.6, 17.4)
-Dementia / 6645 / 83.9 / 54 (52, 56) / 25.1 (24.3, 26.0) / 27.2 / 96.2 / 63 (60, 66) / 50.2 (48.5, 51.8) / 72.8 / 79.4 / 49 (47, 52) / 13.8 (13.1, 14.5)
+Dementia / 407 / 97.1 / 128 (116, 140) / 55.1 (51.2, 59.0) / 42.5 / 100.0 / 104 (92, 116) / 73.9 (69.3, 78.5) / 57.5 / 94.9 / 146 (127, 165) / 40.4 (35.3, 45.6)
-Depression / 5796 / 82.6 / 52 (50, 54) / 24.3 (23.4, 25.2) / 26.1 / 95.8 / 64 (60, 67) / 49.8 (47.9, 51.6) / 73.9 / 78.0 / 47 (44, 50) / 13.2 (12.5, 14.0)
+Depression / 1256 / 94.3 / 85 (79, 91) / 38.5 (36.4, 40.7) / 37.0 / 98.9 / 78 (72, 84) / 60.4 (57.2, 63.6) / 63.0 / 91.5 / 90 (81, 99) / 24.6 (22.2, 27.0)
Appendix Table 4C: For patients age 76-80 years, facility days overall and by survival status at 1 year post-dialysis initiation
Group A: ≥1 facility day in the year post-dialysis initiation / Group B:
Died within 1 year post-dialysis initiation / Group C: Patients from Group B with ≥1 facility day in the year post-dialysis initiation / Group D: Survived to 1 year post-dialysis initiation / Group E: Patients from Group D with ≥1 facility day in the year post-dialysis initiation
Subgroup / Total N / % of total N / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group B / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group D / Mean N(CI) facility days / Mean % (CI) of days spent in a facility
Overall / 6646 / 85.0 / 63 (60, 65) / 30.5 (29.6, 31.5) / 32.5 / 96.3 / 66 (63, 69) / 53.9 (52.4, 55.4) / 67.5 / 79.5 / 61 (58, 64) / 16.9 (16.1, 17.8)
Male / 3565 / 83.5 / 58 (55, 60) / 28.9 (27.7, 30.1) / 33.3 / 95.9 / 62 (58, 66) / 51.0 (48.9, 53.0) / 66.7 / 77.4 / 55 (51, 59) / 15.3 (14.2, 16.4)
Female / 3081 / 86.6 / 68 (65, 72) / 32.3 (31.0, 33.7) / 31.5 / 96.9 / 70 (66, 75) / 57.4 (55.2, 59.7) / 68.5 / 81.8 / 67 (63, 72) / 18.7 (17.4, 20.0)
Non-Black / 5473 / 84.6 / 60 (58, 63) / 30.1 (29.1, 31.1) / 33.3 / 95.9 / 64 (61, 67) / 53.0 (51.3, 54.6) / 66.7 / 78.9 / 58 (55, 62) / 16.2 (15.3, 17.1)
Black / 1173 / 86.6 / 73 (67, 79) / 32.7 (30.5, 35.0) / 29.0 / 98.5 / 76 (68, 83) / 58.7 (54.9, 62.6) / 71.0 / 81.8 / 72 (64, 80) / 19.9 (17.7, 22.1)
-Diabetes / 2374 / 79.8 / 51 (48, 54) / 27.2 (25.7, 28.7) / 31.9 / 94.1 / 57 (53, 61) / 50.4 (47.9, 53.0) / 68.1 / 73.1 / 48 (43, 52) / 13.2 (11.9, 14.4)
+Diabetes / 4272 / 87.8 / 69 (66, 71) / 32.2 (31.1, 33.4) / 32.8 / 97.6 / 70 (67, 74) / 55.7 (53.8, 57.6) / 67.2 / 83.1 / 67 (63, 72) / 18.8 (17.7, 19.9)
-CV disease / 1130 / 65.3 / 43 (38, 48) / 18.7 (16.7, 20.7) / 18.3 / 88.4 / 58 (49, 67) / 43.7 (38.9, 48.5) / 81.7 / 60.1 / 38 (32, 44) / 10.5 (8.8, 12.2)
+CV disease / 5516 / 89.0 / 66 (63, 68) / 32.3 (31.3, 33.3) / 35.4 / 97.2 / 66 (64, 69) / 54.9 (53.3, 56.5) / 64.6 / 84.5 / 65 (62, 69) / 18.1 (17.1, 19.1)
-Dementia / 6122 / 84.2 / 58 (56, 60) / 28.8 (27.9, 29.7) / 31.9 / 96.2 / 64 (61, 67) / 52.6 (51.0, 54.2) / 68.1 / 78.5 / 54 (51, 57) / 15.1 (14.3, 15.9)
+Dementia / 524 / 94.1 / 114 (103, 124) / 49.0 (45.5, 52.5) / 39.9 / 97.6 / 82 (72, 92) / 65.6 (61.0, 70.3) / 60.1 / 91.7 / 136 (119, 152) / 37.3 (32.8, 41.8)
-Depression / 5567 / 83.3 / 56 (54, 58) / 27.6 (26.7, 28.6) / 31.0 / 95.8 / 62 (59, 65) / 51.2 (49.5, 52.9) / 69.0 / 77.6 / 52 (49, 55) / 14.6 (13.7, 15.4)
+Depression / 1079 / 93.6 / 94 (88, 101) / 43.9 (41.5, 46.3) / 40.2 / 98.4 / 80 (73, 86) / 64.3 (61.0, 67.7) / 59.8 / 90.4 / 105 (95, 115) / 28.9 (26.1, 31.7)
Appendix Table 4D: For patients age >80 years, facility days overall and by survival status at 1 year post-dialysis initiation
Group A: ≥1 facility day in the year post-dialysis initiation / Group B:
Died within 1 year post-dialysis initiation / Group C: Patients from Group B with ≥1 facility day in the year post-dialysis initiation / Group D: Survived to 1 year post-dialysis initiation / Group E: Patients from Group D with ≥1 facility day in the year post-dialysis initiation
Subgroup / Total N / % of total N / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group B / Mean N(CI) facility days / Mean % (CI) of days spent in a facility / % of total N / % of Group D / Mean N(CI) facility days / Mean % (CI) of days spent in a facility