Impact of ICU-acquired weakness on post-ICU physical functioning: a follow-up study.
BACKGROUND
ICU-acquired weakness is thought to mediate physical impairments in survivors of critical illness, but few studies have investigated this thoroughly. The purpose was to investigate differences in post-ICU mortality and physical functioning between patients with and without ICU-acquired weakness at 6 months after ICU discharge.


METHODS
ICU patients, mechanically ventilated ≥ 2 days, were included in a single-center prospective observational cohort study. ICU-acquired weakness was diagnosed when the average Medical Research Council score was <4 in awake and attentive patients. Post-ICU mortality was recorded until 6 months after ICU discharge; in surviving patients, physical functioning was assessed using the Short-Form Health Survey physical functioning domain. The independent effect of ICU-acquired weakness on post-ICU mortality was analyzed using a multivariable Cox proportional hazards model. The independent effect of ICU-acquired weakness on the physical functioning domain score was analyzed using a multivariable linear regression model.


RESULTS
Of the 156 patients included, 80 had ICU-acquired weakness. Twenty-three patients died in the ICU (20 with ICU-acquired weakness); during 6 months follow-up after ICU discharge another 25 patients died (17 with ICU-acquired weakness). Physical functioning domain scores were available for 96 survivors (39 patients with ICU-acquired weakness). ICU-acquired weakness was independently associated with an increase in post-ICU mortality (hazard ratio 3.6, 95% confidence interval, 1.3 to 9.8; P = 0.01) and with a decrease in physical functioning (β: -16.7 points; 95% confidence interval, -30.2 to -3.1; P = 0.02).


CONCLUSIONS
ICU-acquired weakness is independently associated with higher post-ICU mortality and with clinically relevant lower physical functioning in survivors at 6 months after ICU discharge.
Department of Intensive Care Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. L.Wieske@amc.uva.nl.|Department of Neurology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. L.Wieske@amc.uva.nl.
Luuk
L
Wieske
Department of Rehabilitation, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. d.s.dettling@amc.uva.nl.
Daniela S
DS
Dettling-Ihnenfeldt
Department of Neurology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. c.verhamme@amc.uva.nl.
Camiel
C
Verhamme
Department of Rehabilitation, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. f.nollet@amc.uva.nl.
Frans
F
Nollet
Department of Neurology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. i.n.vanschaik@amc.uva.nl.
Ivo N
IN
van Schaik
Department of Intensive Care Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. marcus.j.schultz@gmail.com.
Marcus J
MJ
Schultz
Department of Intensive Care Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. j.horn@amc.uva.nl.
Janneke
J
Horn
Department of Rehabilitation, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. m.vanderschaaf@amc.uva.nl.
Marike
M
van der Schaaf
D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D016638:Critical Illness / Q000401:mortality* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007362:Intensive Care Units / Q000639:trends*; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000150:complications / Q000175:diagnosis / Q000401:mortality*; D010351:Patient Discharge / Q000639:trends*; D011446:Prospective Studies; D020127:Recovery of Function; D012121:Respiration, Artificial / Q000009:adverse effects / Q000401:mortality / Q000639:trends; D015996:Survival Rate / Q000639:trends