Postoperative fatigue; translation and validation of a revised 10-item short form of the Identity-Consequence Fatigue Scale (ICFS)

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Highlights

  • Postoperative fatigue is a common problem after otherwise uncomplicated surgery.

  • There are few validated instruments for assessment of Postoperative Fatigue.

  • The 10-item Surgical Recovery Scale (SRS) has three defined fatigue subscales.

  • The SRS is an abridged version of the Identity Consequences Fatigue Scale (ICFS).

  • The 10-item SRS assesses Postoperative Fatigue/Recovery equivalent to the ICFS.

Abstract

Objective

Postoperative fatigue is a common problem after otherwise uncomplicated surgery. It may defer patients from resuming their daily activities and is often reported to be among their most severe symptoms. There are few validated instruments for assessing postoperative fatigue. Our aim was to translate into Norwegian and explore a Short Form of the Identity-Consequences Fatigue Scale; a fatigue questionnaire specifically developed to assess postoperative fatigue.

Methods

The fatigue scale was translated to Norwegian through a forward-backward process, and subsequently validated in a large, mixed surgical population. We performed Principal Component Analyses on the complete 31-item scale and on the 10-item Short Form. The analyses were performed separately on pre- and postoperative data (n = 422 and n = 315, respectively).

Results

The factor analyses confirmed that the translation was valid and revealed three defined dimensions in the 10-item scale. There was no statistically significant difference between means of reported fatigue when measured with the 31- or 10-item scale. Ninety-eight% of change in fatigue from pre- to postoperative status was retained when using the 10-item scale as compared to the 31-item scale.

Conclusion

The abridged, 10-item Short Form performed equal to the 31-item scale and may replace the complete 31-item ICSF scale in exploring the incidence of pre- and post-operative fatigue.

Introduction

Fatigue is a subjective experience, often defined as a persistent tiredness or weakness, being physical, mental or both. It is common in the general population [1], [2] but is also present in a wide range of diseases. When present, it is often reported by patients as being among their most severe and distressing symptoms [3]. It may have impact on physical, behavioural, cognitive and social functioning, imposing restrictions on daily activities, delays resumption of recreational activities and prevents otherwise fit patients from returning to work [4], [5], [6]. Postoperative fatigue (POF) is an often underestimated problem after otherwise uncomplicated surgery [4]. It is most prominent during the first postoperative days, but may last several weeks, and the incidence, severity and duration varies extensively depending on type of surgery performed [6], [7]. POF must be distinguished from residual sedative effects of anaesthetic and analgesic drugs which usually last for less than 8–12 h [8], [9]. POF often affects previously healthy people with little or no baseline fatigue, it has a direct relation to the surgical procedures and perioperative interventions, and it usually has a limited time span; tapering off within days or weeks after the surgery [4], [7], [10].The aetiology of POF is poorly understood, but appears to be multifactorial; involving biological, psychological and social factors [4], [10], [11]. As a consequence, multidimensional assessment tools should be applied in POF research. However, assessment of POF has frequently been assessed only by one-dimensional fatigue scales or multidimensional Quality of Life assessment tools with fatigue as a one-dimensional subscale [4].

A major problem related to POF research has been the use of various non-validated assessment methods [6]. Research based on non-validated assessment tools should generally be viewed with caution. This is also a recognised and comprehensively debated issue in fatigue research in a wide variety of fatigue related diseases [3], [5], [12]. According to a recent review on POF [4], at present only two questionnaires may provide valid and comprehensive assessment of POF; the Fatigue Questionnaire (FQ), presented by Chalder et al. [13] and the Identity-Consequence Fatigue Scale (ICFS), presented by Paddison et al. [14].

The FQ has been translated into Norwegian and validated in a general population [1]. However, this questionnaire is primarily constructed to assess fatigue in patients with chronic fatigue. According to Dittner, if an instrument is developed to measure fatigue in one clinical condition, its use in other patient groups may not be justified [3]. Different scales may be measuring different aspects of fatigue.

The ICFS is directed towards assessing fatigue in a general surgical population, but is quite extensive and time-consuming in a clinical situation. In 2011 Paddison et al. published an abridged version of the ICFS; the 13-item Surgical Recovery Scale (SRS) [15]. A Short Form may be considered favourable, minimising patient burden, thus possibly yielding better patient compliance. The authors' primary aim was to develop a measure responsive to differences in surgical recovery as a single score while being able to retain 90% or more of the variance present in the original measure. They validated the revised short version against quality criteria for health status questionnaires, as proposed by Terwee et al. [16] However, the validation was limited as there was no factor analysis performed on the SRS in order to explore the scale's structure or fatigue subscales. In our opinion it would add to the scale's versatility and usefulness as an outcome measure if subscales also were identified. This would require an Exploratory Factor Analysis. In order to explore the SRS it would be essential to first perform a proper validation of the translated complete 31-item ICFS in a large, mixed patient population.

The aim of this study is to explore the SRS and compare it to the complete 31-item ICFS, in order to consider the Short Form's potential usefulness in assessing postoperative fatigue. This exploration and comparison requires validation of the Norwegian translation of the ICFS.

Section snippets

Translation

The translation followed a forward-backward procedure. To ensure that questions will be easily understood and conceptually equivalent to the original, two persons with Norwegian as their native language, with a thorough knowledge and understanding of the English language, jointly translated the questions in the official ICFS from English to Norwegian. Next, two persons with English as their native language, but speaking and writing Norwegian fluently, separately performed a translation back to

Results

The forward and backward translation procedure ended up with 3 discrepancies which were solved in the next step with full consent between the translators. The final Norwegian ICSF is presented in the Addendum.

A total of 583 patients were considered eligible for the validation study. Of these, 422 patients (72.4%) gave written informed consent and were included in the study and out of these 315 (74.6% of included) completed the study with questionnaire and full data set by post-operative day

Discussion

A primary aim of postoperative fatigue research should be to identify perioperative factors and interventions that could result in less fatigue. Type of surgery and surgical technique is known to influence incidence, duration and severity of POF, while the potential impact of different anaesthetics is hitherto scarcely investigated. Secondarily, postoperative fatigue research may also provide valuable information on the effect of different interventions aimed at reducing or alleviating the

Conclusion

In conclusion, the revised SRS 10-item Short Form may replace the complete 31-item ICSF scale in exploring the incidence of postoperative fatigue and recovery.

There was no statistically significant difference between means of reported fatigue in a large, mixed patient material when measured with the 31- or 10-item scale. This applied for both pre- and postoperative data. Ninety-eight percent of change in fatigue from pre- to postoperative status was retained with the 10-item scale. The abridged

Acknowledgements

We wish to thank Nurse Brith Løfgren and the staff at our Day Surgery Unit for providing invaluable practical and logistical help during the data collection period. We also thank Doctors Simen Doksrød, Øystein Sagen and Randi M Mohus for their helpful contributions during various phases of this work.

Funding source: Telemark Hospital Trust (Project 819707) has been the sole funding source, providing a partial buy-out from consultant practice for Torkjell Nøstdahl.

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  • Cited by (10)

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    The study was conducted at: Department of Anaesthesia, Telemark Hospital Trust, Skien, Norway.

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