Socioeconomic inequalities in patients undergoing abdominal wall reconstruction in the North-West of England, UK: a three-centre retrospective cohort study

It is estimated that 10.8 million general surgical procedures are performed annually in England, UK [1] and approximately 15,000 hospital admissions are attributed to incisional hernia surgery [2]. Abdominal wall reconstruction (AWR) surgery addresses the most complex of incisional hernias, with greater patient co-morbidities and technical demands [3]. The need to understand socioeconomic inequalities in patients undergoing abdominal wall reconstruction (AWR) is paramount because AWR is developing as a distinct surgical sub-specialty and there are increasingly prominent calls to improve care for the management of hernias, which has been historically heterogenous and variable in quality [4‐7]. Understanding individual patients’ needs and their socioeconomic challenges is crucial for informing equitable care. It has been projected that optimal patient care at every stage of the AWR patient journey could lead to savings of £20,000 per patient [2]. Efforts to standardise care offers potential financial benefits to healthcare systems such as the National Health Service (NHS) but also offers potential to improve post-operative outcomes for patients and their quality of life.

Health inequalities, the avoidable differences in health outcomes between specific groups of people, have increased in recent years in the UK and the health gap between the least and most deprived populations has widened [8]. Patients from the most deprived areas are over twice as likely to wait more than a year for elective surgery, compared to those from the least deprived areas [9]. Furthermore, there is growing evidence of disparities in surgical outcomes in many areas of surgery related to socioeconomic deprivation [10‐13]. Data from the national emergency laparotomy audit (NELA) database has demonstrated that patients from deprived backgrounds have greater 30-day mortality and more co-morbid [10]. Socioeconomic deprivation has been linked with higher peri-operative and long term mortality rates in elective colorectal cancer surgery [11], as well as lower survival rates following endometrial cancer surgery, regardless of the stage of the disease at diagnosis [14]. A comprehensive cross-specialty study involving over 9,000 patients who underwent elective surgery demonstrated that those from more deprived backgrounds were subject to greater long-term complications [12]. The published literature on socioeconomic inequalities on ventral hernia surgery outcomes originates primarily from the USA and, most commonly, use insurance status and median household income as indicators of socioeconomic status [15‐20]. Although research in the field of socioeconomic inequalities and health outcomes is rapidly emerging, to our knowledge, there are no published studies based on UK data on the socioeconomic inequalities in ventral hernia surgery outcomes.

Rates of incisional hernias following midline laparotomy have been reported to be up to 40%, depending on the period of follow up [21‐23]. The development of incisional hernias is influenced by multiple factors, including obesity, smoking, comorbidities, and malnutrition, all of which hinder wound healing [24]. In the North-West of England, where there are greater levels of socioeconomic deprivation compared to other areas in the country, there is a higher incidence of cardiometabolic diseases such as hypertension, diabetes, obesity and ischaemic heart disease [25]. The pathways in which socioeconomic deprivation could adversely impact outcomes in patients undergoing AWR is multifaceted and understudied. However, socioeconomic deprivation could manifest adversely through known theorised mechanisms such as delayed health care utilisation [26], poorer health-seeking behaviours and health literacy [27, 28], greater multimorbidity and lifestyle related risk factors [29, 30]. The aim of this study is to (i) understand how patient factors vary by socioeconomic deprivation, and (ii) determine whether patients from more deprived backgrounds have greater adverse outcomes of AWR surgery.

The outcomes of AWR surgery are dependent on patient factors, technical and systems factors, and the wider social determinants of health [34, 35]. Therefore, improving the patient journey, encompassing prevention, diagnosis, treatment, and rehabilitation, is both a social and medical endeavour. This exploratory study provides insights into patient and surgical factors for 234 patients who have undergone AWR across three hospitals in the North-West region of England. The study’s main findings comprise significantly greater unemployment and smoking rates amongst the most deprived quintiles, and a significant difference in minor operative complications and hospital length of stay between the deprivation groups, despite the groups having similar co-morbidities and baseline hernia characteristics.

Working-age individuals residing in the most deprived areas of England are over twice as likely to be unemployed compared to the national average of 8% [36]. Our study population exhibited greater unemployment rates but a similar pattern of socioeconomic disparity, where Q1 had greater unemployment rates (39.2%) compared to Q5 (19%). This is important in the context of patients undergoing AWR as unemployment has a multifaceted adverse impact on health through economic hardship, psychological stress, and resorting to unhealthy behaviours. Longer periods of unemployment has also been linked to greater disease burden [37]. Similarly, patients from deprived backgrounds are less likely to have formal qualifications and have poorer health literacy [38]. These are all factors which could have contributed to the study findings. Specifically, our results showed that socioeconomic deprivation was associated with greater CD1-2 complications and patients from Q2 had significantly greater risk of prolonged hospital stay compared to Q1. Whilst there are no other studies reporting hernia surgery outcomes by socioeconomic deprivation in the UK, similar findings can be seen from US studies, keeping in mind the differences in healthcare systems – insurance-based (US) versus free at the point of use (NHS). Maskal et al. [19] used the distressed community index (DCI), which is formulated using US Census data and is based on seven indicators of neighbourhood prosperity, including employment. They demonstrated in a database study of over 30,000 patients undergoing ventral hernia surgery that higher DCI correlated with re-admission after surgery, re-operation, and had greater surgical site occurrences [19].

Several retrospective studies from the US have reported disparities in hernia surgery outcomes, using median household income (MHI) as an indicator for socioeconomic status, derived from patient zip codes and US Census Bureau data [15, 20, 39]. In a cohort of 478 patients undergoing complex abdominal wall hernias, Marxen et al. demonstrated a significantly increased risk of overall complications and delayed wound healing amongst patients with low MHI [20]. Bowman et al. reported on 321 patients having ventral hernia surgery having greater likelihood of 30-day readmission [15]. Disparities have also been reported in larger national database studies in patients with low MHI undergoing ventral hernia repairs showing prolonged length of stay, greater risk of inpatient mortality and greater overall complication rates [16‐18].

Our findings of greater low-grade complications in the more deprived quintiles could be explained by smoking and diabetes, a known contributory factor to low grade complications such as seromas and wound infections [40]. Within our study population, diabetes was a significant predictor of all grades of post-operative complications, and socioeconomic deprivation was significantly related to having a greater number of current smokers, which is reflective of the disparity seen in large data studies in England [30]. Interestingly, greater rates of prolonged length of stay and CD1-2 complications was observed in the most and least deprived quintiles, which is difficult to explain from the data available.

Understanding the deprivation profile of a patient population is particularly relevant from the standpoint of loco-regional service planning, and crucially, when considering the implementation of a prehabilitation service. There is some evidence that prehabilitation for patients living with obesity leads to reduced risks of complications after abdominal wall reconstruction [41] though the benefits have been better demonstrated in other surgical conditions [42]. Prehabilitation can be integrated within community leisure and health improvement facilities, and it is imperative to identify which localities might experience increased demand to effectively plan and ensure the equitable distribution of resources [43].

Notably, a large proportion (40%) of the patients in this study belonged to the most deprived quintile, and the proportion of patients in each quintile mirrored the distribution of population-level deprivation in the region. Whilst there is no literature to suggest socioeconomic disparities in the prevalence of ventral hernias, there is evidence that some of the risk factors associated with greater hernia occurrence and complications, such as obesity [44] and smoking [45], are more common in more deprived patient groups [30, 46]. It is possible that the prevalence does not significantly vary by deprivation and that the process of selection for an operation in the NHS is non-discriminatory. Alternatively, the true incidence could vary by deprivation, however, as the study only included patients who have undergone elective repair, patients on other pathways will not have been captured. These include patients who have emergency hernia repairs, those on a ‘watch and wait’ pathway, those who are denied surgery altogether (e.g. due to their fitness) and patients who do not present to health services. The difficulty in accurately recording data on these groups of patients, where there is most likely the greatest influence of socioeconomic deprivation, is a challenge in conducting health inequality research in this field. In the UK, a study of Hospital Episode Statistics data reported greater incidence of all types of hernia repairs as an emergency in the most deprived group (23,033 in IMD Q1 vs. 18,614 in Q5) [47]. This could be explained, in part, by greater waiting times in more deprived groups [48], leading to greater rates of obstruction or strangulation [49], necessitating emergency repair.

The IMD is one of the most widely used measures of deprivation in the UK and within its published literature and is helpful in comparing and identifying deprivation profiles of small areas. However, its use is imperfect as it does not accurately identify people’s specific deprivation status, as people from deprived backgrounds may live in non-deprived areas and vice versa. It also doesn’t capture individual factors such as ethnicity and person- specific life experiences contributing to deprivation. Therefore, it could be argued that IMD is a simplified measure of deprivation.

A limitation in the study methodology is having a small sample size compared to larger nationwide studies. Future studies should include patients from a greater geographical area to increase ecological validity. No national hernia database currently exists, and neither would it be possible to link and extract the granular patient and surgical data that this study has reported from NHS England’s Hospital Episode Statistics databases. Future studies should investigate the impact of deprivation and upstream wider determinants of health on the CVH patient journey. This may be best explored through a qualitative study as a quantitative methodology is less suited to capturing intersectionality, the patient’s exposure to experiences which shape their social position and their experiences. It will be possible, as a UK-wide database becomes available, to gain more reliable and generalisable insights into the socioeconomic disparities in AWR surgery.

Over an eight-year period, our study demonstrated some differences in low grade complications and hospital length of stay between the deprivation groups but no difference in high grade complications. It’s possible that the NHS, despite its increasing frailty, has the capacity to avoid the worst complications through equitable care in hospital and equal access to specialist multidisciplinary teams. However, currently, as the NHS faces significant pressures and with growing disparities in healthcare access and health outcomes, the aim must be to optimise NHS functioning to mitigate the impact of socioeconomic deprivation.