Table 1.
Baseline Demographics and Clinical Characteristics among Medicare Beneficiaries based on Dementia Status, 2009–20151,2 (N=4,451,200)
| Prevalent Dementia3 N(%) |
Incident Dementia3 N(%) |
Any Dementia N (%) | No Dementia N(%) | p-value4 | |
|---|---|---|---|---|---|
| Number of beneficiaries | 275717 (6.2) | 63954 (1.4) | 339671 (7.6) | 4111529 (92.4) | <0.0001 |
| Age at enrollment (years) | |||||
| 65–74 | 73111 (26.5) | 23307 (36.4) | 96418 (28.4) | 2532630 (61.6) | <0.0001 |
| 75–84 | 136102 (49.4) | 30494 (47.7) | 166596 (49.0) | 1288545 (31.3) | |
| 85–94 | 63049 (22.9) | 9858 (15.4) | 72907 (21.5) | 276800 (6.7) | |
| Over 95 | 3455 (1.3) | 295 (0.5) | 3750 (1.10) | 13554 (0.3) | |
| Gender | <0.0001 | ||||
| Female | 190536 (69.1) | 41495 (64.9) | 232031 (68.3) | 2373125 (57.7) | |
| Male | 85181 (30.9) | 22459 (35.1) | 107640 (31.7) | 1738404 (42.3) | |
| Race / ethnicity | <0.0001 | ||||
| White | 230288 (83.5) | 53840 (84.2) | 284128 (83.6) | 3570491 (86.8) | |
| Black | 28433 (10.3) | 6380 (10.0) | 34813 (10.2) | 294340 (7.2) | |
| Hispanic | 7735 (2.8) | 1514 (2.4) | 9249 (2.72) | 72724 (1.8) | |
| Asian | 5285 (1.9) | 1277 (2.0) | 6562 (1.93) | 89647 (2.2) | |
| Native American, Other, or Unknown | 3976 (1.4) | 943 (1.5) | 4919 (1.45) | 84327 (2.1) | |
| Geographic Location5 | <0.0001 | ||||
| Rural | 58017 (21.0) | 14234 (22.3) | 72251 (21.3) | 1068645 (26.0) | |
| Urban | 217700 (79.0) | 49720 (77.7) | 267420 (78.7) | 3042884 (74.0) | |
| Year of Study Period Entry | <0.0001 | ||||
| 2009 | 242565 (88.0) | 59712 (93.4) | 302277 (89.0) | 3478438 (84.6) | |
| 2010 | 5804 (2.1) | 1113 (1.7) | 6917 (2.04) | 94767 (2.3) | |
| 2011 | 6628 (2.4) | 1068 (1.7) | 7696 (2.27) | 107498 (2.6) | |
| 2012 | 5937 (2.2) | 743 (1.2) | 6680 (1.97) | 104428 (2.5) | |
| 2013 | 7700 (2.8) | 838 (1.3) | 8538 (2.51) | 163635 (4.0) | |
| 2014 | 5670 (2.1) | 425 (0.7) | 6095 (1.79) | 124845 (3.0) | |
| 2015 | 1413 (0.5) | 55 (0.1) | 1468 (0.43) | 37918 (0.9) | |
| Baseline Eye Care Status6 | <0.0001 | ||||
| No Eye Care Visit | 79983 (29.0) | 22721 (35.5) | 102704 (30.2) | 1151138 (28.0) | |
| Optometrist Only | 50981 (18.5) | 9873 (15.4) | 60854 (17.9) | 665191 (16.2) | |
| Ophthalmologist Only | 99594 (36.1) | 23281 (36.4) | 122875 (36.2) | 1733153 (42.2) | |
| Both Optometrist and Ophthalmologist | 45159 (16.4) | 8079 (12.6) | 53238 (15.7) | 562047 (13.7) | |
| Baseline Cataract Surgery7 | <0.0001 | ||||
| Prior cataract surgery | 31332 (11.4) | 7174 (11.2) | 38506 (11.3) | 549929 (13.4) | |
| No evidence of prior cataract surgery | 244385 (88.6) | 56780 (88.8) | 301165 (88.7) | 3561600 (86.6) | |
| Other Clinical Comorbidities | |||||
| Cataract diagnosis | 99225 (36.0) | 21050 (32.9) | 120275 (35.4) | 1658636 (40.3) | <0.0001 |
| Diabetic Retinopathy diagnosis | 8936 (3.2) | 1717 (2.7) | 10653 (3.14) | 125050 (3.0) | <0.0001 |
| Age-related Macular Degeneration diagnosis | 43911 (15.9) | 7637 (11.9) | 51548 (15.2) | 476757 (11.6) | <0.0001 |
| Glaucoma diagnosis | 52613 (19.1) | 8525 (13.3) | 61138 (18.0) | 747167 (18.2) | <0.0001 |
| Depression diagnosis | 39692 (14.4) | 4731 (7.4) | 44423 (13.1) | 112904 (2.7) | <0.0001 |
| Charlson Comorbidity Index8 | <0.0001 | ||||
| 2–3 | 29406 (10.7) | 13340 (20.9) | 42746 (12.6) | 1582514 (38.5) | |
| 4–5 | 99561 (36.1) | 25416 (39.7) | 124977 (36.8) | 1411249 (34.3) | |
| 6–7 | 81746 (29.6) | 15236 (23.8) | 96982 (28.6) | 702426 (17.1) | |
| 8+ | 65004 (23.6) | 9962 (15.6) | 74966 (22.1) | 415340 (10.1) | |
| Skill Nursing stay | 11702 (4.2) | 978 (1.5) | 12680 (3.73) | 30144 (0.7) | <0.0001 |
2006–2009 data were used to define the lookback period and establish baseline beneficiary characteristics; 2015 data was only applicable for regression analysis since beneficiaries were required to have at least one year of enrollment after the end of the “lookback period.”
Results presented with column percentages for all variables except number of beneficiaries (row percentage)
Prevalent dementia was recorded during the initial 3-year lookback period; incident dementia was a dementia diagnosis that was first recorded during the subsequent follow-up period and prior to first eye care visit during the followup period
Chi-square test statistic
Based on rural urban commuting area codes, in which rural areas represent small urban clusters with a population of 49,000 or fewer persons.
Based on receipt of eye care services during beneficiaries’ “lookback period” (first three years of observed plan enrollment)
Beneficiaries who had evidence of baseline/prior cataract surgery during their initial 3-year lookback period were excluded from the study sample used to identify likelihood of cataract surgery in the subsequent followup period.
We omitted the dementia variable from computation of Charlson Index, such that the lowest permitted Charlson Index score was 2.