Association Between Functional Health Literacy and Postoperative Recovery, Health Care Contacts, and Health-Related Quality of Life Among Patients Undergoing Day Surgery

Key Points

Question

Are there associations between health literacy and postoperative recovery, health care contacts, and quality of life in patients undergoing day surgery?

Findings

In this study of 704 patients who were undergoing day surgery as part of a randomized clinical trial, lower health literacy levels were associated with a low quality of postoperative recovery and quality of life. However, low health literacy levels were not associated with increased health care contacts.

Meaning

Identifying patients with low health literacy and addressing their specific needs are important factors to consider for optimizing the postoperative recovery in day surgery patients.

Abstract

Importance

Day surgery puts demands on the patients to manage their own recovery at home according to given instructions. Low health literacy levels are shown to be associated with poorer health outcomes.

Objective

To describe functional health literacy levels among patients in Sweden undergoing day surgery and to describe the association between functional health literacy (FHL) and health care contacts, quality of recovery (SwQoR), and health-related quality of life.

Design, Setting, and Participants

This observational study was part of a secondary analysis of a randomized clinical trial of patients undergoing day surgery and was performed in multiple centers from October 2015 to July 2016 and included 704 patients.

Main Outcomes and Measures

The primary end point was SwQoR in the FHL groups 14 days after surgery. Secondary end points were health care contacts, EuroQol-visual analog scales, and the Short Form (36) Health Survey in the FHL groups.

Results

Of 704 patients (418 [59.4%] women; mean [SD] age with inadequate or problematic FHL levels, 47 [16] years and 49 [15.1], respectively), 427 (60.7%) reported sufficient FHL, 223 (31.7%) problematic FHL, and 54 (7.7%) inadequate FHL. The global score of SwQoR indicated poor recovery in both inadequate (37.4) and problematic (22.9) FHL. There was a statistically significant difference in the global score of SwQoR (SD) between inadequate (37.4 [34.7]) and sufficient FHL (17.7 [21.0]) (P < .001). The patients with inadequate or problematic FHL had a lower health-related quality of life than the patients with sufficient FHL in terms of EuroQol-visual analog scale scores (mean [SD], 73 [19.1], 73 [19.1], and 78 [17.4], respectively; P = .008), physical function (mean [SD], 72 [22.7], 75 [23.8], and 81 [21.9], respectively; P < .001), bodily pain (mean [SD], 51 [28.7], 53 [27.4], and 61 [27.0], respectively; P = .001), vitality (mean [SD], 50 [26.7], 56 [23.5], and 62 [25.4], respectively; P < .001), social functioning (mean [SD], 73 [28.2], 81 [21.8], and 84 [23.3], respectively; P = .004), mental health (mean [SD], 65 [25.4], 73 [21.2], and 77 [21.2], respectively; P < .001), and physical component summary (mean [SD], 41 [11.2], 42 [11.3], and 45 [10.1], respectively; P = .004). There were no differences between the FHL groups regarding health care contacts.

Conclusions and Relevance

Inadequate FHL in patients undergoing day surgery was associated with poorer postoperative recovery and a lower health-related quality of life. Health literacy is a relevant factor to consider for optimizing the postoperative recovery in patients undergoing day surgery.

Trial Registration

ClinicalTrials.gov Identifier: NCT02492191

This study examines the association between postoperative recovery and functional health literacy in patients undergoing day surgery as part of a randomized clinical trial.

Introduction

In the last decades, more and more surgical procedures have been performed as day surgery.^1,2 Patients are spending less time in the hospital, and this places greater demands on the patients and their relatives. Most of the recovery process after surgery occurs at home without direct supervision from health care professionals.³ Patients undergoing day surgery are therefore provided with oral information and written instructions on how to aid recovery at home.³ Patients in today’s health care system are expected to take part and to be engaged in their own care. Consequently, they have to be able to read and understand health instructions on how to manage their own recovery at home.⁴ Functional health literacy (FHL) is defined as an individual’s capacity to gain access to, and to understand and use, information in ways to promote and maintain good health.⁵ Several studies have raised awareness of health literacy and its consequences for the individual as well as for aspects of health economy.^6,7,8,9

In earlier research, low levels of FHL were shown to be associated with poorer general health,¹⁰ lower health-related quality of life (HRQoL),¹¹ more hospitalizations,^6,7,9,10,12 and a greater use of emergency care.^6,9,10,13 Low health literacy levels are also associated with female sex¹⁰ as well as male sex,¹⁴ fewer years of schooling,^9,10,15 older age,^9,10,15 and lower household income.¹⁵ Preoperatively, there are several associations with low FHL, such as patients’ understanding of perioperative instructions,¹⁶ appointment schedules,⁶ general consent forms,¹⁷ and prescription labels.⁶ Considering this, the association between FHL and postoperative recovery in patients undergoing day surgery needs to be assessed. However, to our knowledge, there are no studies on patients undergoing day surgery that investigate these questions. The aim of this study was to describe functional health literacy levels among patients in Sweden undergoing day surgery and to describe the association between functional health literacy and postoperative recovery, HRQoL, and unplanned health care visits.

Methods

Study Design and Setting

This observational study was part of a multicenter, 2-group, parallel, single-blind randomized clinical trial conducted from October 2015 to July 2016 at 4 day surgery departments in Sweden.¹⁸ The primary outcome for the randomized clinical trial was the cost-effectiveness of using Recovery Assessment by Phone Points (RAPP) for follow-up after day surgery compared with no follow-up with RAPP after day surgery. Recovery Assessment by Phone Points is an electronically assessed follow-up that measures quality of recovery with the Swedish web version of Quality of Recovery (SwQoR) and also enables patients to request a contact telephone call with a nurse from the day surgery department where the surgery was carried out.¹⁹ The study was carried out in accordance with the ethical standards of the Helsinki Declaration (6th revision) and was approved by the Uppsala/Örebro Region ethics committee (2015/262). Oral and written consent was obtained from all participants.

Sample Selection

Inclusion criteria were undergoing day surgery, being 18 years or older, having access to a smartphone, and being able to understand the Swedish language in writing and speech. Exclusion criteria were alcohol and/or drug use, visual impairment, cognitive impairment, or undergoing a surgical abortion. In the main randomized clinical trial, a computer-generated randomization, including random permuted blocks to ensure similar numbers of participants in each group, was used. The randomization was also stratified by center.¹⁸

Questionnaires

The Swedish FHL scale is intended for self-assessment and consists of 5 items on functional skills. The assessments are made on a 5-grade ordinal scale according to how often items agree with the person’s own experiences; that is, never, seldom, sometimes, often, or always (eFigure 1 in the Supplement). The first item focuses on visual ability related to the design of the text and its accessibility, the following 2 deal with understanding words and concepts, the fourth focuses on the ability to persevere in reading, and the last asks about needing help in reading and understanding information. The FHL level of each participant was calculated and the FHL levels were categorized into 3 FHL groups: inadequate (reporting “often” or “always” to 1 or more of the 5 items), problematic (“sometimes” to at least 1 item and not “often” or “always” to any items), or sufficient (responding “never” or “seldom” to all items).²⁰ The Swedish FHL scale has been psychometrically tested in a Swedish population and found to be reliable and valid in terms of content validity.²⁰

The SwQoR measures quality of recovery and is a multi-item questionnaire including 24 items (symptoms/signs) on an 11-point numerical rating scale from 0 (“none of the time”) to 10 (“all of the time”) (eFigure 2 in the Supplement). The global score for SwQoR ranges between 0 (excellent postoperative recovery) and 240 (poor postoperative recovery). The assumption was made in an earlier study that postoperative recovery improves over time, and therefore, analysis was guided by the mean of the total SwQoR score with an indication of good postoperative recovery of less than 31 at day 7 and less than 21 at day 14 indicating a good recovery.²¹ The SwQoR has been psychometrically tested and found to be valid, and has excellent reliability and a high degree of responsiveness.²²

To measure health-related quality of life (HRQoL), the EuroQol-visual analog scale (EQ-VAS; EuroQol Research Foundation)^23,24 and Short Form (SF)-36 Health Survey²⁵ were used. The EQ-VAS consists of a 20-cm vertically graduated visual analog scale with end points (anchors) of 0 (indicating the worst imaginable health state) and 100 (indicating the best imaginable health state).

The SF-36 Health Survey consists of 36 items grouped into 8 multi-item scales that measure physical function, role function, bodily pain, general health, vitality, social functioning, emotional role, and mental health. All scales are scored from 0 to 100, with a higher score indicating better health status. Two summary scores are calculated, the physical component summary and the mental component summary; these summaries reflect overall physical and mental health status.^25,26,27 The validity and reliability of the SF-36 has been shown to be acceptable in a general Swedish population.^25,26,27

To measure health care contacts, a study-specific questionnaire was used. The questionnaire included 5 yes/no questions regarding the number of surgery-related health care contacts with primary care, emergency department (ED), or Sweden’s 24-hour helpline 1177; outpatient hospital visit, or contact via RAPP (this option was only possible for the intervention group). Patients’ age, sex, type of surgery and anesthesia, and American Society of Anaesthesiologists (ASA) class were also collected.

Data Collection

A research nurse was responsible for participants’ inclusion at their day surgery department and made sure that all participants who were eligible for inclusion in the study were offered enrolment. Written information about the study was sent out together with information about the planned surgery. Oral information was provided preoperatively on the day of surgery. Preoperatively, on the day of surgery, the participants answered paper-based questionnaires, SF-36 and EQ-VAS; at 2-weeks postoperatively they answered Swedish FHL and SwQoR as well as the questionnaire regarding contacts with health care during that 2-week period following surgery.

Statistical Analysis

Statistical analyses were conducted using SPSS Statistics, version 24 (IBM) and Microsoft Office Excel, version 2013 (Microsoft). Descriptive analyses were conducted for sociodemographic factors, type of anesthesia and surgery, ASA classification, and SwQoR and HRQoL characteristics. Guided from earlier studies, means and standard deviations were used for SwQoR.^21,28,29,30 The differences between the patients in the 3 FHL groups were analyzed. For nominal data, χ² was used; for ordinal data the Mann-Whitney U test was used for comparisons between 2 groups, and the Kruskal-Wallis test was used for comparisons between 3 groups, and for normally distributed continuous data, 1-way analysis of variance was used. A P value of <.01 was considered statistically significant.

Results

In the main study,¹⁸ 1027 patients were included; of these, 704 patients (68.5%) completed the Swedish FHL questionnaire and constitute the sample of this study. Of these patients, 418 (59.4%) were women and 286 (40.6%) were men. Most (n = 427 [60.6%]) of the 704 patients undergoing day surgery reported sufficient FHL, 223 (31.7%) reported problematic FHL, and 54 (7.7%) reported inadequate FHL. There were no statistical differences between the 3 groups in age, sex, type of anesthesia and surgery, or ASA classification (Table 1).

Table 1. Baseline Characteristics of 704 Patients Undergoing Day Surgery in Different Functional Health Literacy Levels^a.

Variable	FHL, No. (%)			P Value
	Inadequate (n = 54 [7.7%])	Problematic (n = 223 [31.7%])	Sufficient (n = 427 [60.7%])
Age, mean (SD), y	47 (16)	49 (15.1)	47 (14.5)	.27b
Female	32 (59)	130 (58)	256 (60)	.91c
Type of anesthesia
General	38 (75)	154 (74)	315 (77)	.71c
Regional or local	13 (25	55 (26)	93 (23)
Type of surgery
Hand	15 (28)	54 (24)	95 (22)	56c
General	12 (22)	64 (29)	105 (25)
Orthopedic	16 (30)	75 (34)	143 (34)
Gynecology	3 (6)	5 (2)	26 (6)
ENT	6 (11)	14 (6)	47 (11)
Maxillofacial	0	1 (0.5)	1 (0.5)
Urology	0	2 (1)	3 (1)
Eye	0	2 (1)	2 (0.5)
ASA classd
ASA I	26 (48)	105 (47)	212 (50)	.79c
ASA II	14 (26)	75 (34)	112 (26)
ASA III	1 (2)	14 (6)	7 (2)

Abbreviations: ASA, American Society of Anaesthesiologists; ENT, ear, nose, and throat; FHL, functional health literacy.

^aMissing data (ie, rows within subgroups do not always total 100%).

^bOne-way analysis of variance.

^cχ² Test.

^dASA class (I = normal healthy patient, II = patient with mild systemic disease, III = patient with severe systemic disease, IV = patient with severe systemic disease that is a constant threat to life).¹⁹

Functional Health Literacy and Postoperative Recovery

The global score of SwQoR indicated poor recovery in both inadequate (37.2) and problematic (22.9) FHL. There was a statistically significant difference in global score (SD) of SwQoR between inadequate (37.4 [34.7]) and sufficient (17.7 [21.0]) FHL (P < .001). Most differences, 13 of 24 items (54.2%), were found between inadequate and sufficient FHL: trouble breathing (mean [SD], 0.8 [2.1] vs 0.1 [0.8]; P = .002), sleeping difficulties (mean [SD], 2.4 [2.9] vs 0.9 [1.9]; P < .001), not having a general feeling of well-being (mean [SD], 2.7 [3.2] vs 1.0 [1.8]; P < .001), not feeling in control of my situation (mean [SD], 2.1 [2.9] vs 0.7 [1.7]; P < .001), having difficulty feeling relaxed (mean [SD], 2.7 [2.9] vs 0.9 [1.7]; P < .001), voice not sounding the same as usual (mean [SD], 1.0 [2.2] vs 0.3 [1.4]; P < .001), having difficulty taking care of my personal hygiene (mean [SD], 2.6 [3.0] vs 1.0 [2.0]; P < .001), dizziness (mean [SD], 0.8 [1.7] vs 0.3 [1.2]; P = .001), depressed (mean [SD], 2.0 [2.7] vs 0.7 [1.6]; P < .001), anxiety (mean [SD], 1.5 [2.1] vs 0.8 [1.7]; P = .001), sore mouth (mean [SD], 0.5 [1.5] vs 0.2 [0.9]; P = .001), difficulties concentrating (mean [SD], 1.5 [2.3] vs 0.5 [1.3]; P < .001), and fever (mean [SD], 0.6 [1.4] vs 0.2 [0.9]; P < .001) (Table 2).

Table 2. Comparison of Swedish Quality of Recovery Items and Total Score 14 Days After Day Surgery Between Functional Health Literacy Groups (N = 645).

Variables	FHL, Mean (SD)			P Value
	Inadequate (n = 48 [7.4%])	Problematic (n = 205 [31.8%])	Sufficient (n = 392 [60.8%])	Comparison Between All Groupsa	Inadequate vs Problematic FHLb	Inadequate vs Sufficient FHLb	Problematic vs Sufficient FHLb
Trouble breathing	0.8 (2.1)	0.2 (0.6)	0.1 (0.8)	.001	<.001	.002	.34
Sleeping difficulties	2.4 (2.9)	1.7 (2.4)	0.9 (1.9)	<.001	.11	<.001	<.001
Not having a general feeling of well-being	2.7 (3.2)	1.4 (2.2)	1.0 (1.8)	<.001	.01	<.001	.03
Not feeling in control of my situation	2.1 (2.9)	2.3 (2.5)	0.7 (1.7)	<.001	.08	<.001	.001
Having difficulty feeling relaxed	2.7 (2.9)	1.4 (2.2)	0.9 (1.7)	<.001	.004	<.001	.01
Voice not sounding the same as usual	1.0 (2.2)	0.3 (1.1)	0.3 (1.4)	<.001	.001	<.001	.43
Having difficulty taking care of my personal hygiene	2.6 (3.0)	1.5 (2.4)	1.0 (2.0)	<.001	.007	<.001	.02
Having difficulty returning to work or usual home activities	4.4 (4.0)	3.3 (3.4)	2.9 (3.3)	.01	.16	.01	.04
Nausea and/or vomiting	0.7 (1.6)	0.3 (1.0)	0.3 (1.0)	.06	.05	.02	.69
Dizziness	0.8 (1.7)	0.4 (1.2)	0.3 (1.2)	.006	.02	.001	.40
Depressed	2.0 (2.7)	0.9 (1.8)	0.7 (1.6)	<.001	.003	<.001	.11
Anxiety	1.5 (2.1)	1.0 (2.0)	0.8 (1.7)	.004	.03	.001	.13
Headache	1.1 (1.5)	0.7 (1.7)	0.7 (1.8)	.27	.34	.13	.38
Muscle pain	1.7 (2.2)	1.7 (2.5)	1.2 (2.1)	.02	.54	.04	.02
Sore throat	0.3 (1.2)	0.3 (1.0)	0.3 (0.9)	.78	.50	.50	.95
Sore mouth	0.5 (1.5)	0.1 (0.7)	0.2 (0.9)	.004	.001	.01	.29
Difficulties concentrating	1.5 (2.3)	0.9 (1.7)	0.5 (1.3)	<.001	.08	<.001	.001
Trouble urinating	0.2 (0.7)	0.2 (0.9)	0.2 (0.8)	.62	.34	.55	.52
Diarrhea	0.8 (2.1)	0.4 (1.3)	0.2 (1.0)	.09	.22	.04	.23
Feeling constipated	0.8 (2.0)	0.5 (1.4)	0.4 (1.3)	.46	.53	.26	.44
Fever	0.6 (1.4)	0.1 (0.4)	0.2 (0.9)	<.001	<.001	<.001	.51
Pain in the surgical wound	2.6 (3.1)	2.2 (2.6)	1.9 (2.3)	.29	.69	.28	.18
Reddened surgical wound	1.5 (2.3)	1.4 (2.1)	0.9 (1.7)	.20	.47	.13	.21
Swollen surgical wound	1.8 (2.4)	1.5 (2.2)	1.4 (2.1)	.51	.50	.29	.51
Total score SwQoR	37.4 (34.7)	22.9 (25.3)	17.7 (21.0)	<.001	.02	<.001	.02

Abbreviations: FHL, functional health literacy; SwQoR, Swedish Quality of Recovery.

^aKruskal-Wallis test.

^bMann-Whitney U test.

Functional Health Literacy and HRQoL

The patients with inadequate FHL scored lower on EQ-VAS than the patients with sufficient FHL (73 [SD, 19.1] vs 78 [SD, 17.4]; P = .003). The patients in the inadequate FHL group scored also significantly lower on physical function (72 [SD, 22.7] vs 81 [SD, 21.9]; P = .002), bodily pain (51 [SD, 28.7] vs 61 [SD, 27.0]; P = .001), general health (68 [SD, 25.7] vs 75 [SD, 22.4]; P = 001), vitality (50 [SD, 26.7] vs 62 [SD, 25.4]; P < .001), mental health (65 [SD, 25.4] vs 77 [SD, 21.2]; P < .002), and the physical component summary (41 [SD, 11.2] vs 45 [SD, 10.1]; P = .004) than the patients with sufficient FHL. In the comparison between the problematic and sufficient FHL groups, the patients in the problematic FHL group scored significantly lower on physical function (75 [SD, 23.8] vs 81 [SD, 21.9]; P = .003), vitality (56 [SD, 23.5] vs 62 [SD, 25.4]; P = .001), social functioning (81 [SD, 21.8] vs 84 [SD, 23.3]; P = .004), mental health (73 [SD, 21.2] vs 77 [SD, 21.2]; P < .001), and the mental component summary (47 [SD, 12.4] vs 49 [SD, 11.9]; P = .003). When comparing the inadequate and problematic FHL groups, mental health was the only subscore in which the patients in the inadequate FHL group scored significantly lower (65 [SD, 25.4] vs 72 [SD, 21.2]; P = .01) (Table 3). There were no differences between the groups in health care contacts (Table 4).

Table 3. Comparison of Health-related Quality of Life Among the 3 Functional Health Literacy Groups (N = 704).

Variables	FHL			P Value
	Inadequate (n = 54 [7.7%])	Problematic (n = 223 [31.7%])	Sufficient (n = 427 [60.7%])	Comparison Between All Groupsa	Inadequate vs Problematic FHLb	Problematic vs Sufficient FHLb	Inadequate vs Sufficient FHLb
EQ-VAS, mean (SD)	73 (19.1)	73 (19.1)	78 (17.4)	.006	.95	.08	.003
SF-36, mean (SD)
Physical function	72 (22.7)	75 (23.8)	81 (21.9)	<.001	.21	.003	.002
Role function	47 (42.2)	55 (45.0)	59 (44.3)	.09	.30	.04	.19
Bodily pain	51 (28.7)	53 (27.4)	61 (27.0)	.001	.77	.03	.001
General health	68 (25.7)	71 (20.9)	75 (22.4)	.001	.67	.03	.001
Vitality	50 (26.7)	56 (23.5)	62 (25.4)	<.001	.22	.001	<.001
Social functioning	73 (28.2)	81 (21.8)	84 (23.3)	.004	.13	.004	.02
Emotional role	65 (6.0)	72 (39.8)	76 (39.8)	.07	.28	.04	.14
Mental health	65 (25.4)	73 (21.2)	77 (21.2)	<.001	.01	<.001	.002
Physical component summary	41 (11.2)	42 (11.3)	45 (10.1)	.004	.63	.03	.004
Mental component summary	44 (12.6)	47 (12.4)	49 (11.9)	.003	.08	.003	.03

Abbreviations: EQ-VAS, EuroQol visual analog scales; FHL, functional health literacy; SF-36; Short Form 36.

^aKruskal-Wallis test.

^bMann-Whitney U test.

Table 4. Health Care Contacts of Patients Undergoing Day Surgery in Different Functional Health Literacy Levels (N = 704)^a.

Health Care Contacts	FHL, No. (%)			P Valueb
	Inadequate (n = 54 [7.7%])	Problematic (n = 223 [31.7%])	Sufficient (n = 427 [60.7%])
Primary Health Care (n = 647)
Yes	14 (26)	50 (22)	104 (24)	.76
No	37 (69)	147 (66)	287 (67)
Emergency Department (n = 609)
Yes	6 (11)	21 (9)	37 (9)	.55
No	41 (75)	164 (66)	340 (80)
1177 (n = 610)c
Yes	7 (13)	24 (11)	43 (10)	.39
No	42 (78)	159 (71)	335 (78)
Outpatient Hospital (n = 602)
Yes	15 (28)	39 (17)	68 (19)	.37
No	35 (65)	146 (65)	305 (71)
Contact via RAPP (n = 285)d
Yes	5 (28)	16 (17)	29 (17)	.49
No	13 (72)	76 (83)	146 (83)

Abbreviations: FHL, functional health literacy; RAPP, recovery assessment by phone points.

^aMissing data (ie, rows within subgroups do not always total 100%).

^bχ² Test.

^cA 24-hour telephone advice line in Sweden.

^dContact via RAPP was only possible for the intervention group.

Discussion

To our knowledge, this is the first study that has examined whether there is any association between postoperative recovery and functional health literacy in patients undergoing day surgery. We found that patients with inadequate FHL experienced a poor recovery; that is, they reported higher scores in SwQoR on postoperative day 14 compared with patients with sufficient FHL. Patients with problematic FHL also experienced a poor recovery; however, their scores (22.9) were just above the limit for poor recovery (>21).²¹ It has been reported that the quality of recovery is heavily influenced by the patient’s personality traits,³¹ preparedness, coping strategies, knowledge regarding the normal recovery trajectory, and sense of security.^32,33,34 Our results suggest that functional health literacy can now also be included as an influencing factor for the quality of postoperative recovery. Low health literacy levels have, among other factors, been shown to be associated with poorer health-related knowledge and comprehension, including the ability to read and understand perioperative instructions,¹⁶ medication labels, and health messages⁶—skills that are also necessary for patients undergoing day surgery. We agree with the statement of Wright et al,¹² which is also relevant for patients undergoing day surgery, that surgical patients with low health literacy levels need extra time and resources before discharge for information and instruction regarding wound care and dietary changes, arranging home care needs, and managing anxiety regarding self-care.

In our study we also found that an inadequate or problematic level of FHL was associated with lower self-rated QoL when measuring HRQoL with EQ-VAS and SF-36. This finding is in line with previous studies.^11,35 Low FHL has also been reported to have an association with older age^9,10,15 and sex.^10,14 However, in our study we found no association between low FHL and sex or age. Yet, the mean age in our study was low at 47 to 49 years. Neither were there any associations found between low FHL and the type of anesthesia or surgery, or ASA classification.

Concerning the number of health care contacts, low FHL does not seem to have an effect, irrespective of the type of health care contact. Our results are confirmed by Jessup et al¹⁵ who did not find any association between low health literacy levels and a greater use of hospital services, as well as Wright et al,¹² who did not find any association with rates of emergency department visits or hospital readmissions. However, our results, as well as those of Jessup et al¹⁵ and Wright et al,¹² contrast with earlier studies that report that lower health literacy levels were associated with a greater use of emergency care and hospitalization.^6,7,10,13 Yet, the difference could depend on the age of the included study population or the fact that our study, and that of Jessup et al,¹⁵ were performed more recently.

In this study, one of the inclusion criteria was that the participants should have access to a smartphone, because this study was a part of a multicenter randomized clinical trial testing the effect of an electronically assessed postoperative recovery follow-up (RAPP) using a smartphone. Earlier research from the United States has reported that patients with low FHL are less likely to own smartphones or to access and use the internet, particularly for health-related purposes.³⁶ If we had also included those without access to smartphones, the proportion of persons with low FHL might perhaps have been even greater. Still, smartphones are owned by most Swedish people.³⁷

It is important to consider health literacy as a concept when developing an instrument. In this study the patients reported their postoperative recovery using SwQoR. This instrument has been developed through several steps using quantitative and qualitative methods for evaluating the instrument (by patients and health personnel).³⁸ Through several steps, the researchers have considered plain language, the direction of the scale,³⁹ and the wording of the items.⁴⁰ Various revisions have been made, and this process has hopefully successfully developed SwQoR to be easily understood by all patients.

To our knowledge, there are no large studies on health literacy in a Swedish population for comparison. Compared with a study on patients undergoing elective surgical procedures in the Netherlands,⁸ our study had a lower proportion of participants with low health literacy levels. However, compared with the study of Wright et al¹² on patients undergoing major abdominal surgery in the United States, we had the same proportion of patients with inadequate or problematic health literacy. There are earlier studies showing that the frequency of limited health literacy differs depending on which instrument is used to measure health literacy levels.^41,42 Consequently, further studies are needed to confirm these findings.

Limitations

We recognize some possible methodological limitations in our study. First, we do not know if the patients experienced any generalized anxiety disorder or depression preoperatively. On the other hand, there was an association between low preoperative mental health, measured by SF-36, and inadequate FHL. Thereby, there is a risk of false significant findings for those 2 items in SwQoR in measuring depression and anxiety. Still, there are significant associations between poor overall SwQoR and inadequate health literacy.

Second, we have no data on the participants’ education level or socioeconomic status. As a result, we do not know whether those who did not complete the Swedish FHL questionnaire are people with lower levels of education or socioeconomic status and possibly low FHL. This might have resulted in the proportion of patients with sufficient FHL being higher than in the total population. Hence, earlier research has shown an association between low health literacy levels and low socioeconomic status.^43,44 Third, one of our inclusion criteria was the ability to understand the Swedish language in speech and writing. This inclusion criterion excluded, for example, illiterate people and most refugees. In a study by Wångdahl et al,¹³ 60% of the refugees in Sweden had inadequate FHL; this is in contrast to our study in which 54 participants (7.7%) had inadequate FHL. There is a challenge to provide health care on equal terms to vulnerable groups, and there is a need of further research.

Conclusions

Inadequate FHL in patients undergoing day surgery was associated with poorer postoperative recovery and lower HRQoL. Health literacy is a relevant factor to consider for optimizing the postoperative recovery in patients undergoing day surgery.

Supplement 1.

eFigure 1. The Swedish Functional Health Literacy Scale— in English

eFigure 2. The Swedish Web Version of Quality of Recover (SwQoR) in English

Supplement 2.

Trial Protocol