Burden
We found a large diversity in types of burden reported. Table
3 shows a summary of the main findings. A complete overview of all types of burden is presented in Table S2 in Additional file
2.
Table 3
Summary of main findings of the reported burden
Anxietya
| During admission | 42–80 % |
| 3 months | 24–63 % |
| 6 months | 15–24 % |
Depression | During admission | 16–90 % |
| 3 months | 12–26 % |
| 6 months | 5–36 % |
| 12 months | 23–44 % |
Post-traumatic stress disorder | During admission | 57 % |
| 3 months | 30–42 % |
| 6 months | 35–57 % |
| 12 months | 32–80 % |
Employment status | Up to 50 % of the informal caregivers reduced their work hours, quit their job or were fired in order to provide informal care |
Health-related quality of life | Major decreases in mental health, limited changes in physical health |
Use of medication | Between 8 % and 32 % of informal caregivers started to use medications after the ICU admittance of their relative |
Lifestyle interference | Up to 12 months after discharge, almost 50 % of informal caregivers had to quit activities in order to take care of the patient |
Nineteen studies (68 %) assessed depression (Table S3 in Additional file
3), of these eight used the Hospital Anxiety and Depression Scale (HADS) subscale [
17,
26,
32,
34,
36‐
38,
42], seven the Centre for Epidemiological Studies-Depression (CES-D) questionnaire [
18,
22‐
25,
27,
28,
31], one the short version of the CES-D [
20], one the Zarit Burden Inventory [
33], one the Brief Symptom Inventory (BSI) [
30] and one a self-developed questionnaire [
39]. The prevalence was between 16 % and 90 % during ICU or hospital stay and between 12.2 % and 26.2 % 3 months, 4.7 % and 36.4 % 6 months, and 22.8 % and 44 % 12 months after ICU discharge. The cross-sectional study reported a prevalence of 31.9 %.
Ten studies assessed anxiety (36 %) (Table S4 in Additional file
4), of these eight used the HADS [
17,
26,
32,
34,
36‐
38,
42], one the BSI [
30] and one a self-developed questionnaire [
39]. The prevalence was between 42 % and 79.7 % during ICU or hospital stay and between 24.4 % and 62.5 % 3 months and 15 % and 24 % 6 months after ICU discharge.
Post-traumatic stress was assessed in eight studies (29 %) (Table S5 in Additional file
5), of these three used the Impact of Event Scale (IES) [
17,
32,
36], three the IES-Revised (IES-R) [
26,
34,
38], one the PTSD Checklist-specific scale [
44] and one the Post-Traumatic Stress Syndrome-14 screening tool [
35]. The prevalence was 56.8 % during ICU stay and between 29.8 % and 42 % 3 months, 35 % and 57.1 % 6 months and 31.7 % to 80 % 12 months after ICU discharge.
Thirteen studies described informal caregivers’ employment status [
18‐
20,
22‐
25,
27,
29,
31,
32,
43,
44] and at study enrolment between 25.4 % and 72.3 % were in paid employment. Four studies reported a reduction in employment around 2 months after enrolment [
24,
25,
27,
29] and two reported that almost 50 % of caregivers, who had been employed at enrolment, reduced their work hours, quit their job or were fired in order to provide informal care [
24,
29].
Of the informal caregivers, who were employed prior to the ICU admission, 84.6 % had returned to their previous work 12 months after enrolment [
31]. Their mean sick leave was 11 days (range 4–42) for full-time employees and 9 days (range 0–44) for part-time employees during the patient’s ICU stay and 17 days (range 0–124) for full-time employees and 21 days (range 0–106) for part-time employees during the 12 months after ICU discharge [
31]. Thirty-eight percent of the informal caregivers reported that it was somewhat difficult to pay for basic needs such as food, housing, medical care and heating. Some of them even moved to a less expensive home, delayed educational plans or medical care for themselves or another family member, or filed for bankruptcy due to the financial burdens [
29].
Of the seven studies which described health-related quality of life (HRQoL), four used the Short Form 36 (SF-36) [
18,
32,
33,
37], one used the Short Form 8 (SF-8) [
23] and two used a single-measure item [
22,
24] (Table S6 in Additional file
6). Two found no change in physical health scores [
33,
37], one reported that 36 % of informal caregivers experienced negative changes in their physical health [
22], and one reported no statistically significant differences in changes in physical health between informal caregivers and controls over time [
23]. Three studies reported major decreases in the mental health of informal caregivers [
32,
33,
37], one reported that informal caregivers scored lower on all domains of the SF-36 than an age- and gender-matched population [
18], and one reported a slight decrease in general health [
32].
Six studies reported on informal caregivers’ use of antidepressant, anxiolytic, hypnotic and psychotropic medication [
24,
32,
37‐
39,
44]. Between 8.4 % and 32 % of informal caregivers started to use these medications after ICU admittance [
32,
37,
38] and 14 % used more hypnotics and 4 % more anxiolytics after the ICU stay than before [
39]. Between 8.4 % [
32] and 17 % [
38] of informal caregivers received psychiatric or psychological support after their relative’s ICU admission, 40 % saw a healthcare professional for emotional problems [
20]. Six months after ICU admission, 21.1 % had delayed obtaining care for themselves because of the patient’s illness [
29].
Eight studies assessed the lifestyle interference of informal caregivers (Table S7 in Additional file
7). Two used the Activity Restriction Scale [
27,
28], two the Changes in Role Function scale [
19,
25], one the Caregiving Impact Scale [
18], one the “objective indicator” portion of the “objective and subjective burden” tool [
22], one the Family Impact Survey [
29] and one qualitative methods [
42]. Lifestyle interference was high [
19,
27,
28], the percentage of informal caregivers who had quit other activities in order to care for the ICU survivor was 84.5 % 1 month and 45.8 % 12 months after ICU admission [
29]. One month after ICU discharge, 75 % had moderate or great restrictions in visiting friends and 48 % in practicing hobbies and recreation [
19]. They provided about 5 hours of care a day [
22,
25,
27,
43] between hospital discharge [
22] and 12 months after initiation of mechanical ventilation [
27].
Qualitative research
Five studies had qualitative elements. One relied entirely on semi-structured interviews [
21] and four had some qualitative components [
31,
38,
42,
44]. They mainly reported psychosocial burdens, such as sleep disorders, nightmares, sadness, distress, anxiety, exhaustion, crying for no apparent reason and keeping a distance from family and friends. Parents described it as ‘emotionally draining’ to explain the situation to the children [
21] or were scared of leaving children alone with the ICU survivor at home. Children’s involvement made it more complicated to balance the logistics of home life and work [
21,
31]. An ICU admission can also impact the relationship between the ICU survivor and the informal caregiver. Informal caregivers and ICU survivors can feel more irritated with each other, experience less freedom than before [
42], experience a sense of increased distance in their relationship [
21] or even attribute the end of their relationship to the ICU admission [
31]. However, one couple stated that they showed each other more tenderness and respect and another reported that their life was more positive following the ICU admission [
42].