Assessment of Year-to-Year Patient-Specific Comorbid Conditions Reported in the Medicare Chronic Conditions Data Warehouse.

Introduction

The Centers for Medicare & Medicaid Services created the Chronic Conditions Data Warehouse (CCDW) for researchers and health policy analysts seeking to improve health care quality and reduce health care costs and use.[1] Refreshed annually, the CCDW uses International Classification of Diseases (ICD) codes to identify people enrolled in fee-for-service Medicare who have specific chronic conditions, adding flags to denote these individuals.

We sought to determine whether CCDW condition flags identified using codes from the International Classification of Diseases, Ninth Revision (ICD-9) and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) persist in a given patient across time. The CCDW algorithms use different numbers of sequential years, or lookback periods, to flag different conditions. We hypothesized that flags based on longer lookback periods (eg, 3 years for Alzheimer disease) and used for conditions unlikely to be cured (eg, schizophrenia) would be more likely to persist in the same patient than flags based on shorter lookback periods (eg, 1 year for anemia) and conditions with high cure rates (eg, hip and pelvic fracture).

Methods

The Solutions IRB institutional review board and the Centers for Medicare & Medicaid Services approved this cross-sectional study. They determined that informed consent was not required because Medicare enrollees consent to research analysis of their claims data on enrollment and because retroactive collection of informed consent from millions of patients would be impractical. Our work followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline. Using CCDW data from 2010 to 2017, we identified people enrolled in fee-for-service Medicare who had a chronic condition flag that did not exist in the prior year. We limited our analysis to 51 conditions relevant to adults, and we limited the analysis to individuals who survived and remained in fee-for-service Medicare the entire year after they received a chronic condition flag. Using a serial cross-sectional design, we calculated condition persistence, defined as the proportion of enrollees who retained the chronic condition flag the year after they received the flag. We calculated year-to-year and sequential multiyear (up to 5 years) condition persistence. Analyses were conducted using SAS statistical software version 9.4 (SAS Institute) between March 3 and April 27, 2020.

Results

This study included 70 871 475 Medicare fee-for-service beneficiaries (38 285 908 [54.0%] women); the mean (SD) age was 70.9 (12.2) years. Year-to-year condition persistence varied considerably across conditions. Among 188 252 beneficiaries with an acute myocardial infarction flag in 2011, 12 773 beneficiaries retained the flag in 2012 (6.8%). Of 187 664 beneficiaries with hip/pelvic fracture in 2011, 19 110 beneficiaries retained the flag in 2012 (10.2%). Persistence was higher for those with chronic kidney disease, with 1 098 973 of 1 183 808 beneficiaries who had the flag in 2011 retaining it in 2012 (92.8%), and for those with congestive heart failure, with 1 053 944 of 1 096 806 who had the flag in 2011 retaining it in 2012 (96.1%). Among 50 315 beneficiaries with personality disorder who had the flag in 2011, 46 955 beneficiaries (93.3%) retained it in 2012, with similar numbers for numerous other neuropsychiatric disorders (Table 1). Condition flags with shorter lookback periods demonstrated lower year-to-year persistence compared with conditions with longer lookback periods. Flags for conditions amenable to cure (eg, hip or pelvic fracture) were less persistent than flags for conditions not amenable to cure (eg, chronic kidney disease, schizophrenia, and Alzheimer disease). Condition persistence did not differ in 2013 to 2014 (using ICD-9) vs 2016 to 2017 (using ICD-10), with 5 exceptions. Hip/pelvic fracture persistence decreased by 39.4%, from 9.7% (17 764 of 183 690 individuals) to 5.9% (9168 of 156 446 individuals). Alcohol use disorders persistence decreased by 12.3%, from 90.2% (136 830 of 151 778 individuals) to 79.0% (157 388 of 199 151 individuals). Acute myocardial infarction persistence increased by 11.0%, from 5.9% (10 544 of 179 033 individuals) to 6.5% (11 783 of 180 182 individuals). Endometrial cancer persistence increased by 13.0%, from 43.3% (13 097 of 30 251 individuals) to 48.9% (13 522 of 27 649 individuals). Osteoporosis persistence increased by 10.6%, from 34.2% (195 886 of 572 097 individuals) to 37.9% (164 950 of 435 424 individuals). Prostate cancer persistence increased by 10.3%, from 61.9% (78 037 of 126 140 individuals) to 68.2% (70 947 of 104 012 individuals).

Table 1.

Single-Year Persistence for 51 Condition Flags

Condition	Patients with persistent flag, No./total No. (%)a
	2012	2013	2014	2015	2016	2017
3-y lookback b
Alzheimer disease	314 090/327 830 (95.8)	281 421/299 980 (93.8)	252 519/268 953 (93.9)	233 197/244 593 (95.3)	258 878/274 744 (94.2)	256 842/279 732 (91.8)
Alzheimer disease, related disorders, or senile dementia	634 468/660 267 (96.1)	628 580/667 757 (94.1)	582 461/618 691 (94.1)	553 279/579 421 (95.5)	591 821/627 106 (94.4)	627 877/680 800 (92.2)
2-y lookback b
Alcohol use disorders	144 385/158 842 (90.9)	142 043/156 056 (91.0)	136 830/151 778 (90.2)	137 014/150 524 (91.0)	146 993/165 016 (89.1)	157 388/199 151 (79.0)
Anxiety disorders	860 173/961 428 (89.5)	871 403/979 506 (89.0)	838 113/942 733 (88.9)	803 204/894 658 (89.8)	806 205/902 624 (89.3)	832 532/946 830 (87.9)
Bipolar disorders	160 467/174 636 (91.9)	149 896/164 377 (91.2)	144 780/158 678 (91.2)	138 624/151 504 (91.5)	135 555/150 243 (90.2)	134 307/151 047 (88.9)
Blindness and visual impairment	86 638/97 061 (89.3)	78 565/89 081 (88.2)	69 827/79 186 (88.2)	64 754/72 673 (89.1)	49 932/57 563 (86.7)	42 035/48 890 (86.0)
Chronic kidney disease	1 098 973/1 183 808 (92.8)	102 1037/1 116 449 (91.5)	970 515/1 061 005 (91.5)	946 822/1 020 930 (92.7)	1 150 765/1 237 878 (93.0)	1 545 003/1 695 282 (91.1)
Congestive heart failure	1 053 944/1 096 806 (96.1)	900 693/950 720 (94.7)	809 778/855 219 (94.7)	753 384/787 270 (95.7)	728 343/767 652 (94.9)	706 299/759 605 (93.0)
Deafness and hearing impairment	429 279/513 037 (83.7)	420 891/506 310 (83.1)	422 913/507 036 (83.4)	418 026/497 069 (84.1)	417 117/496 617 (84.0)	408 740/494 489 (82.7)
Diabetes	709 018/803 102 (88.3)	595 925/687 417 (86.7)	527 531/608 731 (86.7)	494 838/564 991 (87.6)	463 954/534 729 (86.8)	446 243/522 677 (85.4)
Drug use disorders	158 322/171 498 (92.3)	161 949/176 760 (91.6)	160 278/177 073 (90.5)	169 698/185 388 (91.5)	197 801/218 735 (90.4)	251 466/284 819 (88.3)
Fibromyalgia, chronic pain, and fatigue	834 154/944 217 (88.3)	783 034/893 616 (87.6)	737 255/838 782 (87.9)	741 496/828 414 (89.5)	988 214/1 084 051 (91.2)	1366 664/1 516 034 (90.1)
Ischemic heart disease	1 319 518/1 368 660 (96.4)	1 094 512/1 146 407 (95.5)	940 044/985 737 (95.4)	867 030/899 853 (96.4)	819 059/857 769 (95.5)	812 010/868 720 (93.5)
Liver disease, cirrhosis, and other liver conditions	274 456/326 753 (84.0)	265 490/319 700 (83.0)	260 878/313 163 (83.3)	268 874/317 049 (84.8)	284 083/335 965 (84.6)	310 492/371 871 (83.5)
Major depressive affective disorder	1 013 703/1 114 589 (90.9)	884 626/987 456 (89.6)	801 039/896 264 (89.4)	759 876/843 226 (90.1)	700 115/791 103 (88.5)	635 256/725 392 (87.6)
Migraine and chronic headache	144 546/165 025 (87.6)	141 734/162 608 (87.2)	137 910/158 649 (86.9)	137 676/157 455 (87.4)	161 496/183 253 (88.1)	202 959/233 615 (86.9)
Obesity	674 240/740 342 (91.1)	689 857/763 570 (90.3)	704 988/787 739 (89.5)	727 614/809 000 (89.9)	789 530/877 240 (90.0)	949 166/1 070 484 (88.7)
Opiate use disorder
By any means	77 440/81 631 (94.9)	84 254/89 201 (94.5)	90 167/96 522 (93.4)	100 224/106 864 (93.8)	131 745/142 053 (92.7)	199 780/217 984 (91.6)
By diagnosis	62 087/66 360 (93.6)	72 022/77 219 (93.3)	78 619/85 290 (92.2)	89 276/96 365 (92.6)	107 100/116 511 (91.9)	139 256/154 080 (90.4)
By hospitalization or ED use	60 720/63 082 (96.3)	59 328/61 890 (95.9)	58 258/60 861 (95.7)	59 143/61 587 (96.0)	77 604/82 271 (94.3)	125 930/135 068 (93.2)
By medication-assisted treatment	10 548/10 841 (97.3)	10 841/11 120 (97.5)	13 320/13 718 (97.1)	12 138/12 531 (96.9)	12 719/13 138 (96.8)	13 818/14 611 (94.6)
Peripheral vascular disease	862 189/972 657 (88.6)	753 039/860 743 (87.5)	688 439/784 037 (87.8)	647 746/729 923 (88.7)	642 876/725 439 (88.6)	685 127/782 224 (87.6)
Personality disorder	46 955/50 315 (93.3)	44 973/48 189 (93.3)	43 624/46 953 (92.9)	39 901/43 083 (92.6)	92 631/97 522 (95.0)	169 021/188 303 (89.8)
Posttraumatic stress disorder	47 164/50 648 (93.1)	49 787/53 532 (93.0)	52 555/56 655 (92.8)	55 290/59 277 (93.3)	59 406/64 593 (92.0)	61 768/68 859 (89.7)
Pressure and chronic ulcers	426 168/465 399 (91.6)	389 953/433 263 (90.0)	370 536/411 444 (90.1)	357 504/390 643 (91.5)	334 420/372 030 (89.9)	307 600/348 988 (88.1)
Rheumatoid arthritis/osteoarthritis	1 805 453/2 043 887 (88.3)	1 510 474/1 733 375 (87.1)	1 289 839/1 480 994 (87.1)	1 170 624/1 330 101 (88.0)	1 125 369/1 278 974 (88.0)	112 2508/1 296 795 (86.6)
Schizophrenia	63 664/68 493 (92.9)	54 914/59 464 (92.3)	48 393/52 584 (92.0)	43 597/46 938 (92.9)	41 944/45 527 (92.1)	41 445/46 003 (90.1)
Schizophrenia and other psychotic disorders	264 402/297 644 (88.8)	248 500/284 069 (87.5)	236 981/270 989 (87.5)	234 307/264 550 (88.6)	207 514/238 649 (87.0)	131 188/150 694 (87.1)
Tobacco use disorders	561 405/619 541 (90.6)	486 702/541 532 (89.9)	416 396/466 737 (89.2)	383 472/425 893 (90.0)	336 761/387 263 (87.0)	308 680/356 820 (86.5)
Traumatic brain injury and nonpsychotic mental disorders due to brain damage	43 599/48 032 (90.8)	44 297/48 912 (90.6)	43 078/47 365 (90.9)	44 062/47 879 (92.0)	45 760/50 374 (90.8)	43 845/49 169 (89.2)
Viral hepatitis	59 130/65 154 (90.8)	51 490/57 739 (89.2)	45 436/51 097 (88.9)	43 097/47 924 (89.9)	42 259/47 546 (88.9)	43 317/49 398 (87.7)
1-y lookback b
Acute myocardial infarction	12 773/188 252 (6.8)	11 818/190 412 (6.2)	10 544/179 033 (5.9)	10 448/171 602 (6.1)	11 260/170 900 (6.6)	11 783/180 182 (6.5)
Anemia	1 284 140/2 668 221 (48.1)	884 464/2 015 533 (43.9)	694 609/1 638 903 (42.4)	586 460/1 399 236 (41.9)	526 547/1 253 359 (42.0)	509 837/1 206 981 (42.2)
Asthma	242 455/630 610 (38.4)	174 501/497 164 (35.1)	146 463/436 273 (33.6)	130 075/387 080 (33.6)	111 905/356 738 (31.4)	106 850/323 595 (33.0)
Atrial fibrillation	390 672/684 518 (57.1)	320 347/582 131 (55.0)	287 129/523 176 (54.9)	270 536/489 907 (55.2)	263 730/475 781 (55.4)	254 396/460 922 (55.2)
Benign prostatic hyperplasia	364 448/853 221 (42.7)	263 414/651 777 (40.4)	219 742/560 481 (39.2)	196 195/489 889 (40.0)	190 429/466 747 (40.8)	194 281/469 249 (41.4)
Breast cancer	128 637/222 791 (57.7)	93 004/159 271 (58.4)	79 957/130 592 (61.2)	73 716/114 178 (64.6)	70 656/105 329 (67.1)	69 074/100 795 (68.5)
Cataracts	1 035 571/2 820 229 (36.7)	681 367/2 058 167 (33.1)	534 791/1 667 658 (32.1)	453 214/1 413 359 (32.1)	421 819/1 287 423 (32.8)	408 995/1 230 859 (33.2)
Chronic obstructive pulmonary disease	573 502/1 249 856 (45.9)	408 273/983 330 (41.5)	333 169/844 480 (39.5)	298 545/746 455 (40.0)	290 545/725 184 (40.1)	278 530/695 970 (40.0)
Colorectal cancer	72 812/147 364 (49.4)	53 878/110 533 (48.7)	45 136/90 255 (50.0)	40 480/77 703 (52.1)	38 117/70 373 (54.2)	36 574/66 524 (55.0)
Depression	811 756/1 676 611 (48.4)	587 062/1 295 628 (45.3)	485 523/1 082 983 (44.8)	438 200/969 968 (45.2)	419 798/925 974 (45.3)	392 392/869 121 (45.1)
Endometrial cancer	16 288/39 530 (41.2)	14 041/33 900 (41.4)	13 097/30 251 (43.3)	12 909/28 300 (45.6)	13 188/27 357 (48.2)	13 522/27 649 (48.9)
Glaucoma	369 563/756 249 (48.9)	250 560/551 314 (45.4)	217 946/483 471 (45.1)	196 331/441 690 (44.4)	149 673/397 945 (37.6)	166 280/358 361 (46.4)
Hip/pelvic fracture	19 110/187 664 (10.2)	17 764/183 690 (9.7)	17 253/178 402 (9.7)	16 539/174 661 (9.5)	10 454/166 255 (6.3)	9168/156 446 (5.9)
Hyperlipidemia	1 741 690/2 965 446 (58.7)	905 953/1 720 839 (52.6)	640 399/1 274 510 (50.2)	518 016/1 041 602 (49.7)	451 234/914 684 (49.3)	444 522/864 899 (51.4)
Hypertension	1 743 305/2 641 182 (66.0)	909 547/1 527 034 (59.6)	649 901/1 138 136 (57.1)	524 853/928 957 (56.5)	477 903/828 109 (57.7)	470 725/835 017 (56.4)
Hypothyroidism (acquired)	724 208/1 240 734 (58.4)	443 250/831 392 (53.3)	342 284/664 715 (51.5)	289 944/570 690 (50.8)	259 831/506 275 (51.3)	252 480/495 182 (51.0)
Lung cancer	60 620/94 379 (64.2)	54 382/87 400 (62.2)	51 466/81 358 (63.3)	50 009/77 651 (64.4)	49 824/75 652 (65.9)	49 134/74 235 (66.2)
Osteoporosis	382 253/1 027 502 (37.2)	245 097/715 662 (34.2)	195 886/572 097 (34.2)	175 651/497 189 (35.3)	165 438/461 877 (35.8)	164 950/435 424 (37.9)
Prostate cancer	142 125/229 559 (61.9)	91 931/152 971 (60.1)	78 037/126 140 (61.9)	68 629/107 382 (63.9)	70 226/103 690 (67.7)	70 947/104 012 (68.2)
Stroke/transient ischemic attack	194 645/653 058 (29.8)	164 846/580 292 (28.4)	148 899/521 899 (28.5)	140 738/486 314 (28.9)	131 438/453 023 (29)	134 493/442 561 (30.4)

Counts and percentages represent the number and proportion of beneficiaries who retained the flag in the given year out of those who survived and met inclusion and exclusion criteria in the previous year and continued to meet them in the given year. Criteria included remaining fully enrolled in fee-for-service Medicare.

The number of sequential years of Medicare fee-for-service data used by Chronic Condition Disease Warehouse algorithms to flag the condition.

Multiyear analysis demonstrated a decrease in condition persistence after the lookback period, frequently followed by increasing persistence rates in later years (Table 2). Among 107 individuals who had a hip/pelvic fracture flag that was new in year 0 and who continued to meet inclusion and exclusion criteria for 4 consecutive years, 13 individuals retained that flag in the fifth year (12.1%). Of 1 314 240 individuals who had a hypertension flag that was new in year 0 and who continued to meet inclusion and exclusion criteria for 4 consecutive years, 926 539 individuals retained that flag in the fifth year (70.5%).

Table 2.

Multiyear Persistence for 51 Condition Flags

Condition	Patients with new diagnoses, No.a	Patients with persistent flag, No./total No. (%)b
		1	2	3	4	5
3-y lookback c
Alzheimer disease	1 695 832	1 597 474/1 695 832 (94.2)	1 026 975/1 295 051 (79.3)	450 733/840 919 (53.6)	238 442/359 100 (66.4)	111 471/186 407 (59.8)
Alzheimer disease, related disorders, or senile dementia	3 834 042	3 619 336/3 834 042 (94.4)	2 374 065/3 024 286 (78.5)	1 124 597/2 011 802 (55.9)	628 541/912 251 (68.9)	308 403/501 469 (61.5)
2-y lookback c
Alcohol use disorders	981 367	864 584/981 367 (88.1)	220 508/768 321 (28.7)	103 552/193 917 (53.4)	46 246/90 500 (51.1)	20 178/40 519 (49.8)
Anxiety disorders	5 627 779	501 4351/5 627 779 (89.1)	2 010 094/4 496 855 (44.7)	1 106 832/1 814 479 (61.0)	588 846/996 355 (59.1)	293 559/531 810 (55.2)
Bipolar disorders	950 485	863 991/950 485 (90.9)	319 117/761 615 (41.9)	174 029/288 127 (60.4)	95 145/157 525 (60.4)	49 623/86 905 (57.1)
Blindness and visual impairment	444 454	391 564/444 454 (88.1)	123 421/326 511 (37.8)	56 060/102 299 (54.8)	24 813/46 206 (53.7)	10 554/20 296 (52.0)
Chronic kidney disease	7 315 352	6 730 124/7 315 352 (92.0)	2 775 383/5 981 428 (46.4)	1 515 568/2 448 413 (61.9)	846 231/1 330 552 (63.6)	440 720/743 204 (59.3)
Congestive heart failure	5 217 272	4 951 191/5 217 272 (94.9)	1 958 691/4 304 815 (45.5)	1 106 845/1 669 450 (66.3)	593 425/931 593 (63.7)	296 956/493 283 (60.2)
Deafness and hearing impairment	3 014 558	2 517 156/3 014 558 (83.5)	605 410/2 301 939 (26.3)	281 509/553 063 (50.9)	121 998/256 298 (47.6)	53 799/111 616 (48.2)
Diabetes	3 721 647	3 237 833/3 721 647 (87.0)	1 663 400/2 975 671 (55.9)	1 085 510/1 550 729 (70.0)	693 833/1 011 419 (68.6)	414 964/648 381 (64.0)
Drug use disorders	1 214 273	1 098 917/1 214 273 (90.5)	285 643/981 591 (29.1)	129 811/259 104 (50.1)	57 978/117 128 (49.5)	25 390/52 459 (48.4)
Fibromyalgia, chronic pain, and fatigue	6 105 114	5 451 867/6 105 114 (89.3)	1 887 943/5 007 806 (37.7)	923 129/1 741 752 (53.0)	477 457/846 555 (56.4)	241 812/438 860 (55.1)
Ischemic heart disease	6 127 146	5 851 424/6 127 146 (95.5)	2 371 253/5 340 661 (44.4)	1 461 612/2 152 595 (67.9)	864 630/1 326 120 (65.2)	493 545/784 650 (62.9)
Liver disease, cirrhosis, and other liver conditions	1 984 501	1 664 996/1 984 501 (83.9)	383 916/1 448 741 (26.5)	169 014/336 011 (50.3)	74 862/148 536 (50.4)	33 165/65 934 (50.3)
Major depressive affective disorder	5 358 030	4 795 437/5 358 030 (89.5)	2 098 421/4 247 816 (49.4)	1 170 868/1 864 439 (62.8)	625 626/1 035 805 (60.4)	312 789/552 631 (56.6)
Migraine and chronic headache	1 060 605	925 908/1 060 605 (87.3)	259 594/874 055 (29.7)	128 015/247 134 (51.8)	63 234/121 604 (52.0)	30 771/60 100 (51.2)
Obesity	5 048 375	4 533 441/5 048 375 (89.8)	1 781 231/4 241 027 (42.0)	949 487/1 668 695 (56.9)	476 706/884 427 (53.9)	225 269/442 572 (50.9)
Opiate use disorder
By any means	734 255	683 591/734 255 (93.1)	180 432/611 633 (29.5)	82 655/164 324 (50.3)	36 607/75 015 (48.8)	15 723/33 241 (47.3)
By diagnosis	595 825	548 159/595 825 (92.0)	162 479/492 360 (33.0)	73 256/148 292 (49.4)	31 917/66 494 (48.0)	13 237/28 901 (45.8)
By hospitalization or ED use	464 759	441 056/464 759 (94.9)	66 093/384 260 (17.2)	28 960/57 574 (50.3)	10 754/24 952 (43.1)	4271/9205 (46.4)
By medication-assisted treatment	75 959	73 376/75 959 (96.6)	30 726/67 978 (45.2)	16 125/28 641 (56.3)	8682/15 020 (57.8)	4172/8055 (51.8)
Peripheral vascular disease	4 855 023	4 277 275/4 855 023 (88.1)	1 801 006/3 775 693 (47.7)	1 002 589/1 576 398 (63.6)	538 583/867 284 (62.1)	269 333/464 367 (58.0)
Personality disorders	474 365	436 890/474 365 (92.1)	106 584/394 756 (27.0)	33 642/98 082 (34.3)	15 754/30 770 (51.2)	6990/14 592 (47.9)
Posttraumatic stress disorder	353 564	325 986/353 564 (92.2)	124 621/301 746 (41.3)	63 569/116 001 (54.8)	32 049/59 022 (54.3)	15 065/29 891 (50.4)
Pressure and chronic ulcers	2 421 767	2 186 856/2 421 767 (90.3)	650 651/1 744 373 (37.3)	279 615/518 766 (53.9)	121 361/221 867 (54.7)	50 710/96 775 (52.4)
Rheumatoid arthritis/osteoarthritis	9 164 126	8 027 774/9 164 126 (87.6)	3 718 259/7 496 489 (49.6)	2 166 032/3 482 367 (62.2)	1 234 365/2 016 936 (61.2)	667 189/1 148 346 (58.1)
Schizophrenia	319 009	293 807/319 009 (92.1)	132 411/260 140 (50.9)	80 796/119 521 (67.6)	49 052/72 886 (67.3)	28 542/44 736 (63.8)
Schizophrenia and other psychotic disorders	1 506 595	1 322 790/1 506 595 (87.8)	338 360/1 074 160 (31.5)	161 842/280 975 (57.6)	79 944/135 728 (58.9)	40 413/68 965 (58.6)
Tobacco use disorders	2 797 786	2 492 827/2 797 786 (89.1)	980 326/2 264 033 (43.3)	563 205/892 559 (63.1)	304 860/508 949 (59.9)	157 102/274 654 (57.2)
Traumatic brain injury and nonpsychotic mental disorders due to brain damage	291 731	264 600/291 731 (90.7)	39 322/229 954 (17.1)	13 829/34 573 (40.0)	5002/12 230 (40.9)	1857/4432 (41.9)
Viral hepatitis	318 858	284 740/318 858 (89.3)	111 214/249 358 (44.6)	61 185/98 211 (62.3)	33 107/53 745 (61.6)	17 284/29 246 (59.1)
1-y lookback c
Acute myocardial infarction	1 080 381	69 144/1 080 381 (6.4)	5939/47 894 (12.4)	798/4049 (19.7)	129/518 (24.9)	22/87 (25.3)
Anemia	10 182 233	4 490 365/10 182 233 (44.1)	2 089 591/3 972 606 (52.6)	1 108 858/1 854 277 (59.8)	604 962/978 903 (61.8)	317 640/533 849 (59.5)
Asthma	2 631 460	913 117/2 631 460 (34.7)	395 435/841 350 (47.0)	199 243/366 930 (54.3)	105 190/185 194 (56.8)	53 736/98 237 (54.7)
Atrial fibrillation	3 216 435	1 788 338/3 216 435 (55.6)	979 780/1 600 947 (61.2)	582 960/894 111 (65.2)	345 430/532 250 (64.9)	189 416/314 644 (60.2)
Benign prostatic hyperplasia	3 491 364	1 427 968/3 491 364 (40.9)	627 769/1 313 325 (47.8)	311 052/579 241 (53.7)	161 222/287 383 (56.1)	80 485/149 322 (53.9)
Breast cancer	832 956	514 767/832 956 (61.8)	314 784/477 669 (65.9)	198 873/294 627 (67.5)	121 726/187 271 (65.0)	67 052/115 012 (58.3)
Cataracts	10 477 695	3 530 983/10 477 695 (33.7)	1 321 361/3 450 028 (38.3)	575 943/1 294 255 (44.5)	268 349/563 759 (47.6)	123 765/263 329 (47)
Chronic obstructive pulmonary disease	5 245 275	2 182 034/5 245 275 (41.6)	1 073 219/1 906 251 (56.3)	601 665/943 048 (63.8)	347 928/527 164 (66.0)	191 883/303 613 (63.2)
Colorectal cancer	562 752	287 004/562 752 (51.0)	141 739/241 053 (58.8)	76 796/122 481 (62.7)	41 955/67 560 (62.1)	21 034/37 493 (56.1)
Depression	6 820 285	3 137 331/6 820 285 (46.0)	1 496 017/2 806 786 (53.3)	787 258/1 345 741 (58.5)	426 994/706 944 (60.4)	220 344/383 875 (57.4)
Endometrial cancer	186 987	83 022/186 987 (44.4)	39 011/73 329 (53.2)	19 691/35 225 (55.9)	9851/17 977 (54.8)	4147/9095 (45.6)
Glaucoma	2 989 030	1 351 042/2 989 030 (45.2)	708 742/1 312 485 (54.0)	409 226/688 932 (59.4)	229 512/397 768 (57.7)	109 551/223 574 (49.0)
Hip/pelvic fracture	1 047 118	90 052/1 047 118 (8.6)	6338/69 649 (9.1)	857/4868 (17.6)	155/638 (24.3)	13/107 (12.1)
Hyperlipidemia	8 781 980	4 698 359/8 781 980 (53.5)	2 711 793/4 460 186 (60.8)	1 700 667/2 572 870 (66.1)	1 088 586/1 610 334 (67.6)	673 494/1 031 384 (65.3)
Hypertension	7 898 435	4 778 553/7 898 435 (60.5)	3 002 034/4 494 063 (66.8)	2 039 283/2 828 409 (72.1)	1 402 594/1 913 498 (73.3)	926 539/1 314 240 (70.5)
Hypothyroidism (acquired)	4 308 988	2 313 927/4 308 988 (53.7)	1 337 621/2 147 065 (62.3)	834 148/1 243 141 (67.1)	523 191/773 951 (67.6)	312 178/485 502 (64.3)
Lung cancer	490 675	315 504/490 675 (64.3)	136 069/204 308 (66.6)	70 030/104 678 (66.9)	36 739/57 405 (64.0)	17 831/31 064 (57.4)
Osteoporosis	3 709 751	1 328 091/3 709 751 (35.8)	593 542/1 231 414 (48.2)	298 110/553 079 (53.9)	157 478/278 229 (56.6)	80 415/147 821 (54.4)
Prostate cancer	823 754	522 260/823 754 (63.4)	322 690/484 520 (66.6)	205 279/302 771 (67.8)	128 861/193 485 (66.6)	73 727/121 662 (60.6)
Stroke/transient ischemic attack	3 137 147	916 047/3 137 147 (29.2)	311 105/801 817 (38.8)	127 764/279 571 (45.7)	54 184/115 040 (47.1)	21 668/48 693 (44.5)

Aggregated across 2011 to 2016.

Counts and percentages represent the number and proportion of beneficiaries who retained the flag after a given number of years out of those who survived and met inclusion and exclusion criteria in the previous year and continued to meet them in the given year. Criteria included remaining fully enrolled in fee-for-service Medicare.

The number of sequential years of Medicare fee-for-service data used by Chronic Condition Disease Warehouse algorithms to flag conditions.

Discussion

Using CCDW data from 2010 to 2017, this cross-sectional study found that condition persistence varied considerably across conditions, was not associated with the transition to ICD-10, decreased after the condition-specific lookback period, and then increased over time. The lookback period–associated decrease in condition persistence suggests that a condition was likely to be flagged again if multiple years were used to define the flag.

Our findings did not reveal changes in year-to-year diagnostic categorization when ICD versions changed, which other studies have found.[2,3,4] However, our findings have broader implications for research and policies that relied on CCDW flags, even when ICD versions did not change. Specifically, we found that many individuals diagnosed with a chronic condition were in a CCDW flag–defined cohort 1 year but not in the next, raising concerns that the conclusions of CCDW-based research and policies regarding prevalence, reimbursement, risk adjustment, and quality are inaccurate.

Our study was limited because it analyzed only people enrolled in fee-for-service Medicare and because it used condition flag definitions. Nonetheless, we recommend that researchers seeking to inform reimbursement, risk adjustment, and quality policy aim to conduct sensitivity analyses using multiple years of sequential, condition-specific flags to more confidently identify disease incidence and prevalence and to define cohorts of patients.