Frailty Index: China Health and Retirement Longitudinal Study (CHARLS)

Author

Kwabena Asare

Published

July 2, 2025

1 Introduction

PURPOSE:

  • To create a frailty index in CHARLS.
  • Use the same approach for the frailty Index in MHAS.

Note:

  • CHARLS Data set is already tidied by CWG with all deficit variables available.
  • The frailty deficit coding has also been done for all variables/deficits and labelled with **_fi** suffixes.
  • 4 waves of data collection in CHARLS, 2011, 2013, 2015, 2018.

2 Deficits used in MHAS (39) and availability in CHARLS (36)

  1. Self-report of general health (same as in MHAS)

  2. Ever had high blood pressure (same as in MHAS)

  3. Ever had diabetes (same as in MHAS)

  4. Ever had cancer (same as in MHAS)

  5. Ever had respiratory disease ( combines variable for chronic lung disease with asthma variable)

  6. Ever had heart attack (same as in MHAS)

  7. Ever had stroke ((same as in MHAS)

  8. Ever had arthitis (same as in MHAS)

  9. Fallen down in the last 2 years (same as in MHAS)

  10. Ever fractured a bone since age 50 (same as in MHAS)

  11. Self rated eyesight. Not in harmonised CHARLS dataset.

    • From original CHARLS need to combine eyesight at a distance and eyesight up close.

  12. Self rated hearing. Not in harmonised CHARLS dataset.

    • From original CHARLS: da039 renamed to r*hearing.

  13. Severe fatigue not asked in CHARLS. excluded from CHARLS frailty index

  14. Difficulty breathing. not asked in CHARLS.

    • Have replaced with lung function tests available in waves 1-3 (variables are rpuff1 rpuff2 r*puff3).
    • This paper gives cut-off values for low peak flow in the CHARLS population of 263.83 and 183.64 L/min for men and women, respectively https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.706524/full

  15. Leaks urine when coughing last 2 years (wording is "some difficulty controlling urination and defecation).

  16. Pain in lower limbs while walking. Not in harmonised CHARLS dataset.

    • From original CHARLS.
    • Have replaced with da04 = What part of your body do you feel pain?

  17. Stomach pain, indiestion, diarrhoea (note wording is “ever had stomach/ digestive disease) r*digeste

  18. Frequent problems with pain. Not in harmonised CHARLS dataset.

    • From original CHARLS.
    • Have replaced with troubled with body pain. da041 (recoded to r*bodypain).

  19. CESD - felt depressed (same as in MHAS)

  20. CESD - everything an effort (same as in MHAS)

  21. CESD - restless sleep (same as in MHAS)

  22. CESD - felt happy (same as in MHAS)

  23. CESD - felt lonely (same as in MHAS)

  24. CESD - felt sad not asked in CHARLS. excluded from CHARLS frailty index

  25. CESD - enjoyed life not asked in CHARLS. Have replaced with Feeling hopeful about the future. r*fhopel

  26. CESD - felt tired not asked in CHARLS. excluded from CHARLS frailty index

  27. CESD - had a lot of energy not asked in CHARLS. Have replaced with “Could not get going” as a marker of low energy. r*goingl

  28. Difficulty picking up a coin (same as in MHAS)

  29. Difficulty dressing (same as in MHAS)

  30. Difficulty walking several blocks (same as in MHAS)

  31. Difficulty walking across the room. not asked in CHARLS. Have replaced with Some difficulty climbing several flights of stairs r*climsa

  32. Difficulty bathing or showering (same as in MHAS)

  33. Difficulty eating (same as in MHAS)

  34. Difficulty getting in/out of bed (same as in MHAS)

  35. Difficulty using the toilet (same as in MHAS)

  36. Difficulty preparing hot meals (same as in MHAS)

  37. Difficulty shopping for groceries (same as in MHAS)

  38. Difficulty taking medicines (same as in MHAS)

  39. Difficulty managing money (same as in MHAS)

3 Summary of deficits available in CHARLS by wave

  • Difficulty breathing is not available in wave 4. Variable is generated from lung function tests available in waves 1-3.

  • CESD - Depressive symptoms is a composite of 7 deficits.

    • felt depressed, felt everything is an effort, restless sleep, lonely, could not get going, not happy, not felt hopeful about future

  • Total deficits therefore equals 30

Deficit availabilitys (variables) by wave (CHARLS)
name label wave 1 wave 2 wave 3 wave 4
1 shlta_fi r Self-report of health 1 1 1 1
2 hibpe_fi r Ever had high blood pressure 1 1 1 1
3 diabe_fi r Ever had diabetes 1 1 1 1
4 cancre_fi r Ever had cancer 1 1 1 1
5 hearte_fi r Ever had lung disease or asthma 1 1 1 1
6 stroke_fi r Ever had heart attack 1 1 1 1
7 arthre_fi r Ever had stroke 1 1 1 1
8 chroniclung_fi r Ever had arthritis 1 1 1 1
9 fall_2yr_fi r Fallen down last 2 years 1 1 1 1
10 hipfracture_fi r Ever had hip fracture since last survey 1 1 1 1
11 anysight_fi r Self-rated eyesight 1 1 1 1
12 hearing_fi r Self-rated hearing 1 1 1 1
13 diff_breathing_fi r Difficulty breathing 1 1 1 NA
14 urina_fi r Some difficulty controlling urination and defecation 1 1 1 1
15 bodypain_fi r What part of your body (leg, knee and ankle) do you feel pain? 1 1 1 1
16 lowerlimbpain_fi r Ever had stomach or digestive disease 1 1 1 1
17 digeste_fi r Troubled with body pain 1 1 1 1
1 18 CESD_fi r CESD - Depressive symptoms 1 1 1 1
19 dimea_fi r Difficulty-Picking up a coin 1 1 1 1
20 dressa_fi r Difficulty-Dressing 1 1 1 1
21 walk100a_fi r Difficulty-Walking several blocks 1 1 1 1
22 climsa_fi r Some difficulty climbing several flights of stairs 1 1 1 1
23 batha_fi r Difficulty-Bathing or showering 1 1 1 1
24 eata_fi r Difficulty-Eating 1 1 1 1
25 beda_fi r Difficulty-Getting in/out of bed 1 1 1 1
26 toilta_fi r Difficulty-Using the toilet 1 1 1 1
27 mealsa_fi r Difficulty-Preparing hot meals 1 1 1 1
28 shopa_fi r Difficulty-Shopping for groceries 1 1 1 1
29 medsa_fi r Difficulty-Taking medications 1 1 1 1
30 moneya_fi r Difficulty-Managing money 1 1 1 1
1 CESD - Depressive symptoms is a composite of 7 deficits: felt depressed, felt everything is an effort, restless sleep, lonely, could not get going, not happy, not felt hopeful about future.

4 What percentage of deficits are available and missing by wave in CHARLS?

  • Note: the cut-off based on deficit missingness is 5% for frailty Index in MHAS.
  • Thus, deficits were excluded from frailty calculation in MHAS if more than 5% were missing.
  • Although using 10% cut-off changed nothing in MHAS as the few variables missing were >= 10% missing.

In CHARLS; details in table below:

  • 25/36 deficits are >= 5% missing in at least one wave
  • 17/36 deficits are >= 10% missing in at least one wave
  • In wave 3, 8/36 deficits are >= 19% missing
  • The generated difficulty breathing deficit has 24-100% missing in each round: to automatically exclude
Frailty deficits (variables) availability-missingness by Wave
Characteristic Wave_1 Wave_2 Wave_3 Wave_4
N = 17,7081 N = 18,6121 N = 21,0971 N = 19,8161
1. r Self-report of health



    0 1,099 (6.2%) 1,626 (8.7%) 2,439 (12%) 2,229 (11%)
    0.25 3,030 (17%) 2,530 (14%) 2,569 (12%) 2,348 (12%)
    0.5 8,551 (48%) 9,126 (49%) 10,305 (49%) 8,938 (45%)
    0.75 4,035 (23%) 3,399 (18%) 3,442 (16%) 3,687 (19%)
    1 846 (4.8%) 922 (5.0%) 943 (4.5%) 1,076 (5.4%)
    Missing 147 (0.8%) 1,009 (5.4%) 1,399 (6.6%) 1,538 (7.8%)
2. r Ever had high blood pressure



    0 12,935 (73%) 12,691 (68%) 11,248 (53%) 12,217 (62%)
    1 4,535 (26%) 4,989 (27%) 5,760 (27%) 7,563 (38%)
    Missing 238 (1.3%) 932 (5.0%) 4,089 (19%) 36 (0.2%)
3. r Ever had diabetes



    0 16,346 (92%) 16,222 (87%) 15,207 (72%) 17,254 (87%)
    1 1,062 (6.0%) 1,312 (7.0%) 1,670 (7.9%) 2,538 (13%)
    Missing 300 (1.7%) 1,078 (5.8%) 4,220 (20%) 24 (0.1%)
4. r Ever had cancer



    0 17,319 (98%) 17,426 (94%) 16,709 (79%) 19,346 (98%)
    1 167 (0.9%) 211 (1.1%) 295 (1.4%) 449 (2.3%)
    Missing 222 (1.3%) 975 (5.2%) 4,093 (19%) 21 (0.1%)
5. r Ever had arthritis



    0 15,516 (88%) 15,513 (83%) 14,336 (68%) 16,474 (83%)
    1 1,985 (11%) 2,194 (12%) 2,749 (13%) 3,323 (17%)
    Missing 207 (1.2%) 905 (4.9%) 4,012 (19%) 19 (<0.1%)
6. r Ever had lung disease or asthma



    0 15,337 (87%) 15,226 (82%) 13,896 (66%) 15,884 (80%)
    1 2,130 (12%) 2,429 (13%) 3,067 (15%) 3,899 (20%)
    Missing 241 (1.4%) 957 (5.1%) 4,134 (20%) 33 (0.2%)
7. r Ever had heart attack



    0 17,040 (96%) 17,147 (92%) 16,387 (78%) 18,368 (93%)
    1 486 (2.7%) 557 (3.0%) 678 (3.2%) 1,425 (7.2%)
    Missing 182 (1.0%) 908 (4.9%) 4,032 (19%) 23 (0.1%)
8. r Ever had stroke



    0 11,818 (67%) 11,680 (63%) 9,627 (46%) 12,092 (61%)
    1 5,706 (32%) 6,073 (33%) 7,422 (35%) 7,687 (39%)
    Missing 184 (1.0%) 859 (4.6%) 4,048 (19%) 37 (0.2%)
9. r Fallen down last 2 years



    0 13,691 (77%) 15,343 (82%) 17,356 (82%) 15,627 (79%)
    1 2,549 (14%) 3,056 (16%) 3,557 (17%) 3,805 (19%)
    Missing 1,468 (8.3%) 213 (1.1%) 184 (0.9%) 384 (1.9%)
10. r Ever had hip fracture since last survey



    0 15,980 (90%) 18,245 (98%) 20,475 (97%) 19,213 (97%)
    1 262 (1.5%) 164 (0.9%) 444 (2.1%) 219 (1.1%)
    Missing 1,466 (8.3%) 203 (1.1%) 178 (0.8%) 384 (1.9%)
11. r Self-rated eyesight



    0 106 (0.6%) 215 (1.2%) 189 (0.9%) 153 (0.8%)
    0.125 89 (0.5%) 159 (0.9%) 188 (0.9%) 167 (0.8%)
    0.25 908 (5.1%) 1,119 (6.0%) 1,537 (7.3%) 1,259 (6.4%)
    0.375 675 (3.8%) 754 (4.1%) 856 (4.1%) 750 (3.8%)
    0.5 2,739 (15%) 2,559 (14%) 2,753 (13%) 2,681 (14%)
    0.625 2,494 (14%) 2,372 (13%) 2,404 (11%) 2,285 (12%)
    0.75 4,904 (28%) 5,309 (29%) 7,120 (34%) 7,367 (37%)
    0.875 2,452 (14%) 2,682 (14%) 2,888 (14%) 2,978 (15%)
    1 1,756 (9.9%) 1,596 (8.6%) 1,688 (8.0%) 1,963 (9.9%)
    Missing 1,585 (9.0%) 1,847 (9.9%) 1,474 (7.0%) 213 (1.1%)
12. r Self-rated hearing



    0 253 (1.4%) 443 (2.4%) 472 (2.2%) 414 (2.1%)
    0.25 2,451 (14%) 2,621 (14%) 3,323 (16%) 2,892 (15%)
    0.5 5,333 (30%) 3,760 (20%) 3,464 (16%) 3,601 (18%)
    0.75 7,028 (40%) 7,690 (41%) 10,070 (48%) 10,021 (51%)
    1 2,494 (14%) 2,326 (12%) 2,353 (11%) 2,769 (14%)
    Missing 149 (0.8%) 1,772 (9.5%) 1,415 (6.7%) 119 (0.6%)
13. r Difficulty breathing



    0 8,322 (47%) 7,897 (42%) 11,691 (55%)
    1 4,911 (28%) 4,518 (24%) 4,266 (20%)
    Missing 4,475 (25%) 6,197 (33%) 5,140 (24%) 19,816 (100%)
14. r Some difficulty controlling urination and defecation



    0 16,606 (94%) 17,542 (94%) 19,831 (94%) 18,788 (95%)
    1 757 (4.3%) 737 (4.0%) 916 (4.3%) 908 (4.6%)
    Missing 345 (1.9%) 333 (1.8%) 350 (1.7%) 120 (0.6%)
15. r Ever had stomach or digestive disease



    0 14,097 (80%) 13,959 (75%) 15,744 (75%) 12,411 (63%)
    1 3,413 (19%) 2,768 (15%) 3,948 (19%) 7,326 (37%)
    Missing 198 (1.1%) 1,885 (10%) 1,405 (6.7%) 79 (0.4%)
16. r Troubled with body pain



    0 13,737 (78%) 13,463 (72%) 11,626 (55%) 13,834 (70%)
    1 3,780 (21%) 4,271 (23%) 5,425 (26%) 5,951 (30%)
    Missing 191 (1.1%) 878 (4.7%) 4,046 (19%) 31 (0.2%)
17. r What part of your body (leg, knee and ankle) do you feel pain?



    0 11,862 (67%) 10,762 (58%) 13,849 (66%) 7,820 (39%)
    1 5,665 (32%) 523 (2.8%) 5,843 (28%) 1,595 (8.0%)
    Missing 181 (1.0%) 1,885 (10%) 1,405 (6.7%) 79 (0.4%)
    0.25
2,970 (16%)
6,048 (31%)
    0.5
1,408 (7.6%)
2,334 (12%)
    0.75
1,064 (5.7%)
1,940 (9.8%)
18. r CESD - Depressive symptoms



    No (score is zero) 1,600 (9.0%) 1,452 (7.8%) 2,425 (11%) 1,998 (10%)
    Yes (score not zero) 14,427 (81%) 15,094 (81%) 17,175 (81%) 15,984 (81%)
    Missing 1,681 (9.5%) 2,066 (11%) 1,497 (7.1%) 1,834 (9.3%)
19. r Difficulty-Picking up a coin



    0 16,814 (95%) 17,488 (94%) 19,832 (94%) 18,650 (94%)
    1 721 (4.1%) 766 (4.1%) 903 (4.3%) 1,047 (5.3%)
    Missing 173 (1.0%) 358 (1.9%) 362 (1.7%) 119 (0.6%)
20. r Difficulty-Dressing



    0 16,460 (93%) 17,363 (93%) 19,535 (93%) 18,318 (92%)
    1 906 (5.1%) 941 (5.1%) 1,235 (5.9%) 1,379 (7.0%)
    Missing 342 (1.9%) 308 (1.7%) 327 (1.5%) 119 (0.6%)
21. r Difficulty-Walking several blocks



    0 16,021 (90%) 17,062 (92%) 19,228 (91%) 18,037 (91%)
    1 268 (1.5%) 1,215 (6.5%) 1,519 (7.2%) 1,661 (8.4%)
    Missing 1,419 (8.0%) 335 (1.8%) 350 (1.7%) 118 (0.6%)
22. r Some difficulty climbing several flights of stairs



    0 10,460 (59%) 10,452 (56%) 12,334 (58%) 10,744 (54%)
    1 6,958 (39%) 7,479 (40%) 8,207 (39%) 8,953 (45%)
    Missing 290 (1.6%) 681 (3.7%) 556 (2.6%) 119 (0.6%)
23. r Difficulty-Bathing or showering



    0 16,175 (91%) 17,066 (92%) 19,205 (91%) 18,021 (91%)
    1 1,181 (6.7%) 1,216 (6.5%) 1,540 (7.3%) 1,675 (8.5%)
    Missing 352 (2.0%) 330 (1.8%) 352 (1.7%) 120 (0.6%)
24. r Difficulty-Eating



    0 16,838 (95%) 17,883 (96%) 20,238 (96%) 19,154 (97%)
    1 531 (3.0%) 421 (2.3%) 531 (2.5%) 542 (2.7%)
    Missing 339 (1.9%) 308 (1.7%) 328 (1.6%) 120 (0.6%)
25. r Difficulty-Getting in/out of bed



    0 16,394 (93%) 17,256 (93%) 19,357 (92%) 18,285 (92%)
    1 973 (5.5%) 1,047 (5.6%) 1,408 (6.7%) 1,411 (7.1%)
    Missing 341 (1.9%) 309 (1.7%) 332 (1.6%) 120 (0.6%)
26. r Difficulty-Using the toilet



    0 15,354 (87%) 16,157 (87%) 18,096 (86%) 17,447 (88%)
    1 2,013 (11%) 2,145 (12%) 2,668 (13%) 2,249 (11%)
    Missing 341 (1.9%) 310 (1.7%) 333 (1.6%) 120 (0.6%)
27. r Difficulty-Preparing hot meals



    0 15,939 (90%) 16,622 (89%) 18,902 (90%) 17,467 (88%)
    1 1,597 (9.0%) 1,686 (9.1%) 1,944 (9.2%) 2,254 (11%)
    Missing 172 (1.0%) 304 (1.6%) 251 (1.2%) 95 (0.5%)
28. r Difficulty-Shopping for groceries



    0 15,886 (90%) 16,749 (90%) 19,055 (90%) 17,825 (90%)
    1 1,636 (9.2%) 1,568 (8.4%) 1,788 (8.5%) 1,896 (9.6%)
    Missing 186 (1.1%) 295 (1.6%) 254 (1.2%) 95 (0.5%)
29. r Difficulty-Taking medications



    0 16,298 (92%) 17,418 (94%) 19,812 (94%) 18,567 (94%)
    1 1,223 (6.9%) 924 (5.0%) 1,050 (5.0%) 1,154 (5.8%)
    Missing 187 (1.1%) 270 (1.5%) 235 (1.1%) 95 (0.5%)
30. r Difficulty-Managing money



    0 15,254 (86%) 16,307 (88%) 18,598 (88%) 17,417 (88%)
    1 2,248 (13%) 1,936 (10%) 2,186 (10%) 2,304 (12%)
    Missing 206 (1.2%) 369 (2.0%) 313 (1.5%) 95 (0.5%)
1 n (%)
CESD components deficit availability-missingness by Wave; to include missingness cut-off?
Characteristic wave 1 wave 2 wave 3 wave 4
N = 17,7081 N = 18,6121 N = 21,0971 N = 19,8161
r CESD-Felt depressed 1,848 (10%) 2,280 (12%) 1,742 (8.3%) 2,209 (11%)
r CESD-Everything an effort 1,818 (10%) 2,249 (12%) 1,733 (8.2%) 2,230 (11%)
r CESD-Sleep was restless 1,717 (9.7%) 2,114 (11%) 1,568 (7.4%) 1,957 (9.9%)
r CESD-Felt lonely 1,784 (10%) 2,191 (12%) 1,659 (7.9%) 2,098 (11%)
r Could not get going 1,822 (10%) 2,226 (12%) 1,754 (8.3%) 2,265 (11%)
r CESD-Felt happy 1,760 (9.9%) 2,174 (12%) 1,705 (8.1%) 2,076 (10%)
r Felt hopeful about the future 2,077 (12%) 2,560 (14%) 2,301 (11%) 2,839 (14%)
1 n (%)

5 How many deficits (distribution) are available by observation in each wave

  • Note: cut-off based on number of missing deficits per observation was 20% in MHAS
  • Thus any observation with more than 20% of included deficits missing had missing Frailty Index
  • 20% of 30 = 6, of 29 = 5.8, of 26 = 5.2, of 21 = 4.2, to round down to the nearest whole number
Number of available deficits per observation by wave
Characteristic Wave_1 Wave_2 Wave_3 Wave_4
N = 17,7081 N = 18,6121 N = 21,0971 N = 19,8161
Number of available deficits



    30 11,687 (66%) 10,696 (57%) 11,827 (56%)
    29 3,684 (21%) 4,789 (26%) 3,708 (18%) 17,614 (89%)
    28 557 (3.1%) 478 (2.6%) 414 (2.0%) 374 (1.9%)
    27 97 (0.5%) 126 (0.7%) 106 (0.5%) 1,567 (7.9%)
    26 105 (0.6%) 73 (0.4%) 44 (0.2%) 57 (0.3%)
    25 997 (5.6%) 169 (0.9%) 41 (0.2%) 78 (0.4%)
    24 257 (1.5%) 670 (3.6%) 276 (1.3%) 4 (<0.1%)
    23 87 (0.5%) 633 (3.4%) 736 (3.5%) 2 (<0.1%)
    22 22 (0.1%) 305 (1.6%) 2,383 (11%)
    21 12 (<0.1%) 256 (1.4%) 935 (4.4%)
    20 8 (<0.1%) 38 (0.2%) 53 (0.3%) 25 (0.1%)
    19 20 (0.1%) 14 (<0.1%) 11 (<0.1%) 1 (<0.1%)
    18 7 (<0.1%) 10 (<0.1%) 6 (<0.1%) 1 (<0.1%)
    17 6 (<0.1%) 23 (0.1%) 15 (<0.1%)
    16 4 (<0.1%) 58 (0.3%) 75 (0.4%) 3 (<0.1%)
    15 12 (<0.1%) 43 (0.2%) 179 (0.8%) 6 (<0.1%)
    14 5 (<0.1%) 9 (<0.1%) 14 (<0.1%) 6 (<0.1%)
    13
15 (<0.1%) 75 (0.4%) 1 (<0.1%)
    12 2 (<0.1%) 7 (<0.1%) 28 (0.1%) 1 (<0.1%)
    11
4 (<0.1%) 4 (<0.1%)
    10 2 (<0.1%) 5 (<0.1%) 1 (<0.1%)
    9 2 (<0.1%) 4 (<0.1%)
11 (<0.1%)
    8 5 (<0.1%) 1 (<0.1%) 1 (<0.1%) 15 (<0.1%)
    7 1 (<0.1%) 2 (<0.1%) 4 (<0.1%) 13 (<0.1%)
    6 1 (<0.1%) 4 (<0.1%) 2 (<0.1%) 8 (<0.1%)
    5
2 (<0.1%)
4 (<0.1%)
    4
4 (<0.1%) 4 (<0.1%) 6 (<0.1%)
    3
6 (<0.1%) 9 (<0.1%) 1 (<0.1%)
    2 1 (<0.1%) 25 (0.1%) 14 (<0.1%)
    1 12 (<0.1%) 41 (0.2%) 21 (<0.1%) 5 (<0.1%)
    0 115 (0.6%) 102 (0.5%) 111 (0.5%) 13 (<0.1%)
1 n (%)

6 Create Frailty Index

  • Sum frailty deficit codes for each observation (i.e, for all deficits)

  • Then divide total score per observation by total number of included deficits (by wave)

  • Frailty Index Versions: based on number of deficits included due to deficit exceeding % missing threshold (i.e proportion of the deficit missing)

    • Version 5% missing:
      • In waves 1, 2, 3, 4 … 6, 11, 15, 3 deficits had >= 5% missing
      • Thus 24/30, 19/30, 15/30, 26/30 deficits available in waves 1, 2, 3, 4 based on 5% missing cut-off
    • Version 10% missing:
      • In waves 1, 2, 3, 4 … 1, 2, 9, 1 deficits had >= 10% missing
      • Thus 29/30, 26/30, 21/30, 29/30 deficits available in waves 1, 2, 3, 4 based on 10% missing cut-off

  • Then if more than 20% of included deficits are missing, set frailty Index = missing

6.1 Check the specific deficits to exclude by wave based on 5% and 10% missing thresholds

Wave 1, 10% cut-off
No. deficit percent_missing
1 r1diff_breathing_fi 25.27106
Wave 2, 10% cut-off
No. deficit percent_missing
1 r2diff_breathing_fi 33.29572
2 r2bodypain_fi 10.12787
3 r2lowerlimbpain_fi 10.12787
4 r2CESD_fi 11.10037
Wave 3, 10% cut-off
No. deficit percent_missing
1 r3hibpe_fi 19.38190
2 r3diabe_fi 20.00284
3 r3cancre_fi 19.40086
4 r3hearte_fi 19.59520
5 r3stroke_fi 19.11172
6 r3arthre_fi 19.18756
7 r3chroniclung_fi 19.01692
8 r3diff_breathing_fi 24.36365
9 r3digeste_fi 19.17808
Wave 4, 10% cut-off
No. deficit percent_missing
1 r4diff_breathing_fi 100
Wave 1, 5% cut-off
No. deficit percent_missing
1 r1fall_2yr_fi 8.290038
2 r1hipfracture_fi 8.278744
3 r1anysight_fi 8.950757
4 r1diff_breathing_fi 25.271064
5 r1CESD_fi 9.492885
6 r1walk100a_fi 8.013327
Wave 2, 5% cut-off
No. deficit percent_missing
1 r2shlta_fi 5.421234
2 r2hibpe_fi 5.007522
3 r2diabe_fi 5.791962
4 r2cancre_fi 5.238556
5 r2hearte_fi 5.141844
6 r2anysight_fi 9.923705
7 r2hearing_fi 9.520739
8 r2diff_breathing_fi 33.295723
9 r2bodypain_fi 10.127874
10 r2lowerlimbpain_fi 10.127874
11 r2CESD_fi 11.100365
Wave 3, 5% cut-off
No. deficit percent_missing
1 r3shlta_fi 6.631275
2 r3hibpe_fi 19.381903
3 r3diabe_fi 20.002844
4 r3cancre_fi 19.400863
5 r3hearte_fi 19.595203
6 r3stroke_fi 19.111722
7 r3arthre_fi 19.187562
8 r3chroniclung_fi 19.016922
9 r3anysight_fi 6.986775
10 r3hearing_fi 6.707115
11 r3diff_breathing_fi 24.363654
12 r3bodypain_fi 6.659715
13 r3lowerlimbpain_fi 6.659715
14 r3digeste_fi 19.178082
15 r3CESD_fi 7.095796
Wave 4, 5% cut-off
No. deficit percent_missing
1 r4shlta_fi 7.761405
2 r4diff_breathing_fi 100.000000
3 r4CESD_fi 9.255147

6.2 Create Frailty Index: version 10% and 5% deficit missing cut-off

7 Distribution of frailty score by wave

Continuous and categorical frailty (5% and 10% missig deficit cut-off) by wave
Characteristic Wave1 Wave2 Wave3 Wave4
N = 17,7081 N = 18,6121 N = 21,0971 N = 19,8161
frailty_10



    Mean (SD) 0.17 (0.12) 0.16 (0.12) 0.18 (0.14) 0.21 (0.14)
    Median (IQR) 0.14 (0.09, 0.23) 0.13 (0.08, 0.21) 0.14 (0.09, 0.24) 0.17 (0.11, 0.27)
    Range 0.00, 0.83 0.00, 0.82 0.00, 0.99 0.00, 0.89
    Missing 324 417 542 122
frailty_5



    Mean (SD) 0.17 (0.13) 0.11 (0.13) 0.10 (0.15) 0.19 (0.14)
    Median (IQR) 0.14 (0.07, 0.22) 0.05 (0.00, 0.16) 0.07 (0.00, 0.13) 0.16 (0.09, 0.25)
    Range 0.00, 0.92 0.00, 0.95 0.00, 1.00 0.00, 0.89
    Missing 195 274 199 120
frailty_10_cat



    Not Frail 13,752 (78%) 15,044 (81%) 15,706 (74%) 13,881 (70%)
    Frail 3,632 (21%) 3,151 (17%) 4,849 (23%) 5,813 (29%)
    Missing 324 (1.8%) 417 (2.2%) 542 (2.6%) 122 (0.6%)
frailty_5_cat



    Not Frail 13,852 (78%) 16,088 (86%) 18,371 (87%) 14,332 (72%)
    Frail 3,661 (21%) 2,250 (12%) 2,527 (12%) 5,364 (27%)
    Missing 195 (1.1%) 274 (1.5%) 199 (0.9%) 120 (0.6%)
1 n (%)

8 Codebook of frailty calculation

The table below summarizes the the methods and definitions for the frailty score calculation

Health deficits included in Frailty Index and their coding
Deficit description Deficit coding
1 r Self-report of health Excellent = 0, Very good = 0.25, Good = 0.5, Fair = 0.75, Poor = 1
2 r Ever had high blood pressure no = 0, yes = 1
3 r Ever had diabetes no = 0, yes = 1
4 r Ever had cancer no = 0, yes = 1
5 r Ever had arthritis no = 0, yes = 1
6 r Ever had lung disease or asthma no = 0, yes = 1
7 r Ever had heart attack no = 0, yes = 1
8 r Ever had stroke no = 0, yes = 1
9 r Fallen down last 2 years no = 0, yes = 1
10 r Ever had hip fracture since last survey no = 0, yes = 1
11 r Self-rated eyesight mean of self rated eyesight at a distance plus self rated eyesight up close each coded as Excellent = 0, Very good = 0.25, Good = 0.5, Fair = 0.75, Poor = 1
12 r Self-rated hearing Excellent = 0, Very good = 0.25, Good = 0.5, Fair = 0.75, Poor = 1
13 r Difficulty breathing no = 0, yes = 1
14 r Some difficulty controlling urination and defecation no = 0, yes = 1
15 r Ever had stomach or digestive disease no = 0, yes = 1
16 r Troubled with body pain waves 1 and 3 (no = 0, yes = 1); waves 2 and 4 (1 = 0, 2 = 0.25, 3 = 0.5, 4 = 0.75, 5 = 1)
17 r What part of your body (leg, knee and ankle) do you feel pain? no = 0, yes = 1
18 r CESD - Depressive symptoms mean of felt depressed, everything is an effort, restless sleep, lonely, could not get going coded as 1=0 2=0.33 3=0.66 4=1 and happy, felt hopeful about future coded as 1=1 2=0.66 3=0.33 4=0
19 r Difficulty-Picking up a coin no = 0, yes = 1
20 r Difficulty-Dressing no = 0, yes = 1
21 r Difficulty-Walking several blocks no = 0, yes = 1
22 r Some difficulty climbing several flights of stairs no = 0, yes = 1
23 r Difficulty-Bathing or showering no = 0, yes = 1
24 r Difficulty-Eating no = 0, yes = 1
25 r Difficulty-Getting in/out of bed no = 0, yes = 1
26 r Difficulty-Using the toilet no = 0, yes = 1
27 r Difficulty-Preparing hot meals no = 0, yes = 1
28 r Difficulty-Shopping for groceries no = 0, yes = 1
29 r Difficulty-Taking medications no = 0, yes = 1
30 r Difficulty-Managing money no = 0, yes = 1