Clinical Frailty Scale in prediction of mortality, disability and quality of life for patients in need of intensive care

Clinical Frailty Scale (CFS) is an assessment tool used to describe the frailty of a patient. The scale originated in Canada and was initially developed to estimate the need for institutional care and to predict life expectancy. The CFS version currently used has 9 levels (CFS-9) where an assessment of frailty is made between 1, very fit, to 9, terminally ill.

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SBU Enquiry Service

Consists of structured literature searches to highlight studies that can address questions received by the SBU Enquiry Service from Swedish healthcare or social service providers. We assess the risk of bias in systematic reviews and when needed also quality and transferability of results in health economic studies. Relevant references are compiled by an SBU staff member, in consultation with an external expert when needed.

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Published: Report no: ut202023 Registration no: SBU 2020/393 https://www.sbu.se/ut202023e

Question

Is the Clinical Frailty Scale able to predict mortality, disability or quality of life in patients admitted to intensive care, either due to respiratory tract infection or due to other cause?

Summary

SBU Enquiry Service identified 23 primary studies considered within the scope of the review question after literature search and study selection. Eleven studies were critically appraised as low to moderate risk of bias regarding at least one outcome. In the included studies, the Clinical Frailty Scale (CFS) was used to estimate the frailty of individuals prior to admission to intensive care. The included studies were mainly conducted on elderly patients in need of intensive care, where the cause of need for intensive care varied. None of the studies examined patients who exclusively had respiratory tract infections. The studies were published from 2014 and onwards, and most studies during the last two years. Most studies originated from Europe and Canada. Several were multicentre studies, in which some had participation from Swedish clinics. The studies that were appraised as having a low to moderate risk of bias are briefly described in the text below, and all studies are presented in Table 1 and in Appendix 3 and 4.

SBU Enquiry Service identified:

  • Eight studies examined the validity and reliability of CFS in patients in intensive care (low to moderate risk of bias) [1–8]. Seven of these studies examined the prediction of mortality [1–5,7,8].
  • Two studies evaluated to which degree CFS could predict future disability for patients in intensive care (moderate risk of bias) [4,6].
  • One study examined to which degree CFS could predict future quality of life for patients in intensive care (moderate risk of bias) [4].
  • Four studies examined interrater reliability for CFS in patients in intensive care (low to moderate risk of bias) [2,3,9,10].

In studies with low to moderate risk of bias, the results showed that frailty assessment with CFS to some extent could predict in-hospital mortality and 30-day mortality. The mortality increased with each unit of the frailty scale. DeGeer et al. 2020, found that frailty assessment with CFS could predict 30-day mortality with an AUC (area under curve) of 0.74 (95% CI, 0.9 to 0.79) [1]. Two studies analysed the optimal threshold value for predicting mortality, with the aim of being able to use the scale dichotomously and found that mortality substantially increased from scale-point CFS 5 and above [1,5].

In the study by Hope et al. 2019, the risk of disability at six months was associated with an increase per unit on the CFS scale [6]. In the study by Brummel et al. 2017, the risk of disability varied depending on the assessment tool used to assess disability level, as well as on the time of assessment. Regarding prediction of quality of life, the results presented by Brummel et al showed varying results [4].

It should be noted that no study showed that CFS was able to predict either outcome (mortality, disability or quality of life) of all individuals. This implies that, there will be patients who are assessed as having a high level of frailty but do not die within 30 days, as well as patients who are assessed as having a low level of frailty but that nevertheless die.

Table 1. Identified studies according to age and outcome (reference, risk of bias)

a Measures disability or death at 6 months as a combined endpoint.
b Also presents 1-year mortality.
c Also presents 6 months mortality.
d These articles are based on the same patient material.
  Outcome
Age ICU mortality
In-hospital mortality		 30-day mortality 90-day mortality Disability Quality of life Test-retest reliability
≥18 years
7 studies		 Shears et al
2018, [3]
Moderate Fernando et al
2019, [11]
High
Montgomery et al
2019, [12]
High		 De Geer et al
2020, [1]
Low		 Brummel et al
2017, [4]
Moderate		 Brummel et al
2017, [4]
Moderate
Hope et ala
2017, [13]
High		 Brummel et al
2017, [4]
Moderate		 Shears et al
2018, [3]
Moderate
≥50 years
6 studies		 Bagshaw et alb
2014, [8]
Moderate (for this outcome)
Darval l et alc
2019, [14]
High
Kara et al
2018 [15]
High
Tipping et al
2019, [16]
High		     Hope et ald
2019, [6]
Moderate		 Bagshaw et al
2014, [8]
High (for this outcome)		 Hope et ald
2019, [9]
Moderate
≥60 years
1 study		 Pugh et al
2019, [10]
High (for this outcome)		         Pugh et al
2019, [10]
Moderate (for this outcome)
≥65 years
3 studies		 Langlais et al
2018, [7]
Moderate
Fernando et al
2019, [17]
High
Le Maguet et alc
2014, [18]
High		          
≥70 years
1 study		   Silva-Obregon et al
2020, [19]
High		 Silva-Obregon et al
2020, [19]
High		 Silva-Obregon et al
2020, [19]
High		    
≥80 years
3 studies		 Guidet et al
2020, [2]
Low
Flaatten et al
2017, [5]
Low
Darvall et al
2019, [20]
High		 Guidet et al
2020, [2]
Low
Flaatten et al
2017, [5]
Low		       Guidet et al
2020, [2]
Low
Age not reported
2 studies		 Fisher et al
2018, [21]
High		         Pugh et al
2017, [22]
High

Appendices

Appendix 1 Critical appraisal checklist.pdf

Appendix 2 Excluded studies.pdf

Appendix 3 Table of included studies.pdf

Appendix 4 Studies appraised as high risk of bias.pdf

Literature search

PubMed via NLM 20 04 01 
Frailty assessment in the critically ill using Clinical frailty scale
Search terms Items found
The search result, usually found at the end of the documentation, forms the list of abstracts.; [MeSH] = Term from the Medline controlled vocabulary, including terms found below this term in the MeSH hierarchy; [MeSH:NoExp] = Does not include terms found below this term in the MeSH hierarchy; [MAJR] = MeSH Major Topic; [TIAB] = Title or abstract; [TI] = Title; Systematic[SB] = Filter for retrieving systematic reviews; * = Truncation
Population:
1. “Critical Care”[Mesh] 56 746
2. “Intensive Care Units”[Mesh] 82 287
3. “Critical Illness”[Mesh] 27 989
4. critical care[Title/Abstract] 29 925
5. Critical illness[Title/Abstract] 8 819
6. critically ill[Title/Abstract] 43 135
7. Intensive care[Title/Abstract] 140 634
8, ICU[Title/Abstract] 54 277
9. 1-8 (OR) 248 489
10 “Airway Management”[Mesh] 133 633
11. “Respiratory Insufficiency”[Mesh] 63 557
12. Influenza, Human[Mesh] 48 335
13. Pneumonia[Mesh] 90 785
14. Ventilat*[Title/Abstract] 162 458
15. Respirat*[Title/Abstract] 485 671
16. Airway*[Title/Abstract] 159 850
17. Intubat*[Title/Abstract] 55 233
18. Influenza[Title/Abstract] 94 940
19. Pneumoni*[Title/Abstract] 177 432
20. Pulmonary[Title/Abstract] 535 174
21 Lung*[Title/Abstract] 633 130
22. 10-21 (OR) 1 782 341
23. 9 OR 22 1 967 584
24. “Severe Acute Respiratory Syndrome Coronavirus 2”[Supplementary Concept] 353
25. severe acute respiratory syndrome coronavirus 2[Title/abstract] 183
26. 2019nCoV[Title/Abstract] 394
27. 2019-nCov[Title/Abstract] 402
28. CoVID-19[Title/Abstract] 1 758
29. CoVID19[Title/Abstract] 1 749
30. SARS-CoV-2[Title/Abstract] 614
31. CoVid[Title/Abstract] 1 772
32. nCov[Title/Abstract] 419
33. novel coronavirus[Title/Abstract] 1 143
34. new coronavirus[Title/Abstract] 163
35. coronavirus 2019[Title/Abstract] 228
36. SARS coronavirus 2[Title/Abstract] 5
37. 24-36 (OR) 2 850
38. “Severe Acute Respiratory Syndrome”[Mesh] 4 484
39. “SARS Virus”[Mesh] 2 916
40. Severe acute respiratory syndrome[Title/Abstract] 4 807
41. SARS[Title/Abstract] 9 046
42. SARS-CoV[Title/Abstract] 2 915
43. 38-42 (OR) 10 581
44. “Coronavirus Infections”[Mesh:NoExp] 4 679
45. “Middle East Respiratory Syndrome Coronavirus”[Mesh] 982
46. MERS[Title/Abstract] 4 156
47. MERS-CoV[Title/Abstract] 1 563
48. Middle East respiratory syndrome[Title/Abstract] 1 818
49. Middle East respiratory syndrome-related coronavirus[Title/Abstract] 10
50. EMC/2012 15
51. 44-50 (OR) 7 923
52. 37 OR 43 OR 51 18 852
53. 23 OR 52 1 977 403
Intervention:
54. Clinical frailty scale[Title/Abstract] 295
55. Csha-cfs[Title/Abstract] 19
56. frailty index[Title/Abstract] 1 238
57. 54 OR 55 OR 56 1 489
Combined sets:
58. 23 AND 57 183
59. 53 AND 57 183
Limits:
60. 59 and limit 2017 - 133
Final 60   133

 

Embase via embase.com 20 04 01 
Frailty assessment in the critically ill using Clinical frailty scale
/de = Term from the EMTREE controlled vocabulary; /exp = Includes terms found below this term in the EMTREE hierarchy; /mj = Major Topic; :ab = Abstract; :au = Author; :ti = Article Title; :ti,ab = Title or abstract; * = Truncation; ’ ’ = Citation Marks; searches for an exact phrase
Search terms Items found
Population:
1. ‘intensive care’/exp 699 967
2. ‘intensive care unit’/exp 186 548
3. ‘critical illness’/exp 28 616
4. ‘critically ill patient’/exp 42 781
5. ‘critical care’:ti,ab,kw 45 100
6. ‘critical illness’:ti,ab,kw 11 979
7. ‘critically ill’:ti,ab,kw 63 867
8. ‘intensive care’:ti,ab,kw 202 584
9. ‘icu’:ti,ab,kw 111 350
10. 1-9 (OR) 916 778
11. ‘assisted ventilation’/exp 168 620
12. ‘respiratory failure’/exp 101 148
13. ‘virus pneumonia’/exp 15 552
14. ‘viral respiratory tract infection’/exp 3 886
15. ‘ventilat*’:ti,ab,kw 239 525
16. ‘respirat*’:ti,ab,kw 651 176
17. ‘airway*’:ti,ab,kw 229 402
18. ‘intubat*’:ti,ab,kw 86 825
19. ‘influenza’:ti,ab,kw 111 342
20. ‘pneumoni*’ :ti,ab,kw 249 310
21. ‘pulmonary’:ti,ab,kw 730 432
22. ‘lung*’:ti,ab,kw 932 588
23. 11-22 (OR) 2 435 961
24. 10 OR 23 3 035 795
25. ‘coronavirus disease 2019’/exp 166
26. ‘sars-related coronavirus’/de 46
27. ‘severe acute respiratory syndrome coronavirus 2’:ti,ab,kw 113
28. ‘2019-ncov’:ti,ab,kw 344
29. ‘covid-19’:ti,ab,kw 1 104
30. ‘covid19’:ti,ab,kw 9
31. ‘sars-cov-2':ti,ab,kw 401
32. ‘covid’:ti,ab,kw 1 117
33. ‘ncov’:ti,ab,kw 359
34. ‘novel coronavirus’:ti,ab,kw 1 016
35. ‘new coronavirus’:ti,ab,kw 151
36. ‘coronavirus 2019’:ti,ab,kw 194
37. ‘sars coronavirus 2’:ti,ab,kw 7
38. 25-37 (OR) 2 199
39. ‘severe acute respiratory syndrome’/exp 8 242
40. ‘sars coronavirus’/exp 4 858
41. ‘severe acute respiratory syndrome’:ti,ab,kw 4 956
42. ‘sars’:ti,ab,kw 9 674
43. ‘sars-cov’:ti,ab,kw 2 804
44. 39-43 (OR) 14 056
45. ‘middle east respiratory syndrome coronavirus’/exp 1 886
46. ‘middle east respiratory syndrome’/exp 1 031
47. ‘mers’:ti,ab 4 456
48. ‘mers-cov’:ti,ab 1 659
49. ‘middle east respiratory syndrome’:ti,ab 1 905
50. ‘emc/2012’:ti,ab 24
51. 45-50 (OR) 5 253
52. 38 OR 44 OR 51 19 516
53. 24 OR 52 3 044 399
Intervention:
54. ‘clinical frailty scale’/exp 128
55. ‘frailty index’/exp 185
56. ‘clinical frailty scale’:ab,ti,kw 604
57. ‘csha-cfs’:ab,ti,kw 34
58. ‘frailty index’:ab,ti,kw 2 001
59. 54-58 (OR) 2 592
Combined sets
60. 24 AND 59 428
61. 53 AND 59 428
Limits:
62. 61 limit 2017 - 284
Final   284

 

Scopus via scopus.com 20 04 01 
Frailty assessment in the critically ill using Clinical frailty scale
The search result, usually found at the end of the documentation, forms the list of abstracts.; TITLE-ABS-KEY = Title or abstract or keywords; * = Truncation
Search terms Items found
Population:
1. TITLE-ABS-KEY(“critical care”) 70 360
2. TITLE-ABS-KEY(“critical illness”) 44 195
3. TITLE-ABS-KEY(“critically ill”) 59 453
4. TITLE-ABS-KEY(“intensive care”) 289 685
5. TITLE-ABS-KEY(ICU) 66 375
6. 1-5 (OR) 349 952
7. TITLE-ABS-KEY(ventilat*) 347 495
8. TITLE-ABS-KEY(respirat*) 1 097 689
9. TITLE-ABS-KEY(airway) 228 056
10. TITLE-ABS-KEY(intubat*) 115 733
11. TITLE-ABS-KEY(influenza) 151 754
12. TITLE-ABS-KEY(pneumoni*) 370 746
13. TITLE-ABS-KEY(pulmonary) 775 658
14. TITLE-ABS-KEY(lung) 1 471 367
15. 7-14 (OR) 2 938 457
16. 6 OR 15 3 152 556
17. TITLE-ABS-KEY ( "severe acute respiratory syndrome coronavirus 2" ) 308
18. TITLE-ABS-KEY ( "2019-ncov" ) 259
19. TITLE-ABS-KEY ( "covid-19" ) 796
20. TITLE-ABS-KEY ( "covid19" b) 3
21. TITLE-ABS-KEY ( "sars-cov-2" ) 248
22. TITLE-ABS-KEY ( "covid" ) 804
23. TITLE-ABS-KEY ( "ncov" ) 276
24. TITLE-ABS-KEY ( "novel coronavirus" ) 871
25. TITLE-ABS-KEY ( "new coronavirus" ) 152
26. TITLE-ABS-KEY ( "coronavirus 2019" ) 151
27. TITLE-ABS-KEY ( "sars coronavirus 2" ) 14
28. 17-27 (OR) 1 634
29. TITLE-ABS-KEY ( "severe acute respiratory syndrome" ) 10 545
30. TITLE-ABS-KEY ( "sars" ) 100 532
31. TITLE-ABS-KEY ( "sars-cov" ) 2 765
32. 29-31 (OR) 103 904
33. TITLE-ABS-KEY ( "mers" ) 32 349
34. TITLE-ABS-KEY ( "mers-cov" ) 1 587
35. TITLE-ABS-KEY ( "middle east respiratory syndrome" ) 2 576
36. TITLE-ABS-KEY( "emc/2012" ) 41
37. 33-36 (OR) 33 120
38. 28 OR 32 OR 37 136 593
39. 16 OR 38 3 272 784
Intervention:
40. TITLE-ABS-KEY(“clinical frailty scale”) 330
41. TITLE-ABS-KEY(csha-cfs) 21
42. TITLE-ABS-KEY(“frailty index”) 1 356
43. 40-42 (OR) 1 635
Combined sets:
44. 16 AND 43 280
45. 39 AND 43 280
Limits:
46. 45 limit 2017 - 203
Final   203

 

CINAHL via ebsco.com 20 04 01 
Frailty assessment in the critically ill using Clinical frailty scale
The search result, usually found at the end of the documentation, forms the list of abstracts.; AB = Abstract; DE = Term from the thesaurus; MM = Major Concept; TI = Title; * = Truncation; “ “ = Citation Marks; searches for an exact phrase
Search terms Items found
Population:
1. MH “Critical Care” 23 830
2. MH “Critical Illness” 12 216
3. MH “Critically Ill Patients” 13 452
4. MH “Intensive Care Units” 40 072
5. MH “Respiratory Care Units” 181
6. TI "critical care" OR AB "critical care" 23 198
7. TI "Critical illness" OR AB "Critical illness" 4 474
8. TI "critically ill" OR AB "critically ill" 21 775
9. TI "Intensive care" OR AB "Intensive care" 64 499
10. TI "ICU" OR AB "ICU" 28 650
11. 1-10 (OR) 126 925
12. MH “Respiration, Artificial+” 33 869
13. MH “Respiratory Failure+” 14 861
14. MH “Airway Management+” 21 225
15. MH “Ventilator Patients” 2 659
16. MH “Pneumonia, Viral” 728
17. MH “Influenza, Human” 5 978
18. TI "ventila*" OR AB "ventilat*" 49 016
19. TI "respirat*" OR AB "respirat*" 89 112
20. TI "airway*" OR AB "airway*" 34 603
21. TI "intubat*" OR AB "intubat*" 17 001
22. TI "influenza" OR AB "influenza" 19 137
23. TI "pneumoni*" OR AB "pneumoni*" 34 343
24. TI "pulmonary" OR AB "pulmonary" 95 961
25. TI "lung*" OR AB "lung*" 108 749
26. 12-25 (OR) 353 075
27. 11 OR 26 445 634
28. TI "severe acute respiratory syndrome coronavirus 2" OR AB "severe acute respiratory syndrome coronavirus 2” 14
29. TI "2019 nCoV" OR AB "2019 nCoV” 2
30. TI “2019-nCov” OR AB “2019-nCov” 75
31. TI CoVID-19 OR AB CoVID-19 233
32. TI CoVID19 OR AB CoVID19 2
33. TI SARS-CoV-2 OR AB SARS-CoV-2 43
34. TI “SARS CoV 2” OR AB “SARS CoV 2” 1
35. TI CoVid OR AB CoVid 3
36. TI nCov OR AB nCov 9
37. TI “novel coronavirus” OR AB “novel coronavirus” 231
38. TI “new coronavirus” OR AB “new coronavirus” 39
39. TI "coronavirus 2019” OR AB coronavirus 2019” 90
40. 28-39 (OR) 479
41. MH “Severe Acute Respiratory Syndrome” 1 997
42. MH “SARS Virus” 158
43. TI “Severe acute respiratory syndrome” OR AB “Severe acute respiratory syndrome” 1 056
44. TI SARS OR AB SARS 2 304
45. TI SARS-CoV OR AB SARS-CoV 99
46. 41-45 (OR) 3 332
47. MH “Middle East Respiratory Syndrome Coronavirus” 372
48. MH “Middle East Respiratory Syndrome” 245
49. TI MERS OR AB MERS 959
50. TI MERS-CoV OR AB MERS-CoV 400
51. TI “Middle East respiratory syndrome” OR AB “Middle East respiratory syndrome” 611
52. TI “Middle East respiratory syndrome-related coronavirus” OR AB “Middle East respiratory syndrome-related coronavirus” 2
53. TI “EMC/2012” OR AB “EMC/2012” 4
54. 47-53 (OR) 1 195
55. 40 OR 46 OR 54 4 711
56. 27 OR 55 446 435
Intervention:
57. TI “clinical frailty scale” OR AB “clinical frailty scale” 202
58. TI “csha-cfs” OR AB “csha-cfs” 14
59. TI “frailty index” OR AB “frailty index” 728
60. 57-59 (OR) 903
Combined sets:
61. 27 AND 60 105
62. 56 AND 60 105
Limits:
63. 62 limit 2017 - 67
Final   67
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