“Almost half the adult population is living with chronic pain,” the Daily Mail reports. A major new review suggests that around 28 million adults in the UK are affected by some type of chronic pain (pain that lasts for more than three months).

The researchers used data from 19 studies that included almost 140,000 adults. They extrapolated the results to come up with the estimate that around 43% of people in the UK experience chronic pain. More adults aged 75 or over (62%) experienced pain than those aged 18 to 25 (14.3%).

There are limitations to this study that affect the reliability, the main one being that this type of review can only be as good as the included studies. In this case, there weren’t many good-quality studies and there was a lot of variation in their findings.

With an ageing population, it is likely that the prevalence of chronic pain will increase and the need for pain management and relief will grow.

A case could be made that health services across the world need to do more to meet the needs of people with chronic pain. While it may not be life-threatening, chronic pain can cause considerable distress and adversely affect mental health.

Current advice for chronic pain is to use a combination of physical exercise and painkillers to relieve pain. Psychological therapies, such as cognitive behavioural therapy, can also help people cope better with quality of life issues.

Where did the story come from?

The study was carried out by researchers from Imperial College London, Arthritis Research UK and the University of Aberdeen. Funding was provided by the British Pain Society and Arthritis Research UK.

Conflict of interest was declared by one of the researchers who had received fees from pharmaceutical companies including Grunenthal, Napp/Mundipharma, Pfizer, Astrazeneca, BioQuiddity and The Medicines Co, outside the submitted work.

The study was published on an open access basis in the peer-reviewed medical journal BMJ Open, so you can read it for free online.

This has been reported widely by the UK media, which generally provided an accurate account of the research findings. However, limitations of the included studies that might reduce reliability were not mentioned.

What kind of research was this?

This was a systematic review and meta-analysis which aimed to combine existing data on the prevalence of chronic pain in the general population. The researchers investigated various definitions of chronic pain to attempt to provide national estimates.

A systematic review is the best way of combining all available data on a health issue. However, the limitation is that it can only be as reliable as the included studies – if these are of poor quality, then the findings of a systematic review should be interpreted with caution.

Similarly, the results of a meta-analysis may be subject to question if there was a great deal of difference (heterogeneity) between individual studies.

What did the research involve?

The review team searched two medical databases, Medline and Embase, for articles reporting on the prevalence of chronic pain in the general UK population. All study types were included, providing they reported prevalence estimates for the following:

chronic pain – pain in one or more locations in the body

chronic widespread pain – using the American College of Rheumatology (ACR) definition (1990) of pain in the head or spine and two limbs on opposite side of the body

fibromyalgia – ACR criteria (1990 or 2010) of widespread pain and tenderness in many different parts of the body, along with other symptoms of the condition (e.g. lethargy)

nerve pain (neuropathic pain) – pain in one or more body locations with nerve features, such as numbness or tingling

Each definition of pain was to be present for at least three months.

The researchers excluded studies containing data prior to 1990, or if it was not representative of the UK population, or it was not possible to retrieve UK-specific estimates. They also excluded studies investigating specific pain sites only (e.g. prevalence of lower back pain only), or studies in specific populations who wouldn’t represent the general population (e.g. chronic pain prevalence in people with diabetes).

Two researchers reviewed search results, selected studies which met their criteria, and collected prevalence data.

All included studies were assessed using a risk of bias tool. Studies that had a very high risk of bias were not included in the analysis.

Statistical methods were used to combine the findings of individual studies.

What were the basic results?

The database searches found 1,737 potentially relevant studies. On further examination, only 19 met their inclusion criteria, presenting data from 139,933 adults in the UK. Most of these (13) were cross-sectional studies, and the remainder were cohort studies.

The review found that 43.5% of people experienced chronic pain of some kind (pooled results from seven studies). Prevalence ranged from 35% to 51% in the individual studies. The prevalence of moderate to severely disabling chronic pain was lower and ranged from 10.4% to 14.3% (based on four studies).

The researchers split estimates for chronic pain into age groups and, as you might expect, found a theme for increasing prevalence with increasing age. This ranged from 14.3% in younger adults (18 to 25 years old), to 62% for those over 75 years of age.

Findings using the three other pain definitions were:

chronic widespread pain – 14.2% (pooled result from five studies)

chronic neuropathic pain – 8.2% to 8.9% (results in two studies)

fibromyalgia – 5.4% (one study)

How did the researchers interpret the results?

The researchers conclude: “Chronic pain affects between one-third and one-half of the population of the UK, corresponding to just under 28 million adults, based on data from the best available published studies. This figure is likely to increase further in line with an ageing population.”

Conclusion

This systematic review aimed to combine available data on the prevalence of chronic pain in the UK adult population.

The 19 identified studies suggested that 43% of people in the UK experience chronic pain. However, there are both strengths and limitations to this review that may affect the reliability of this finding.

The review has strengths in the careful search methods which aimed to identify only studies relevant to the general population. The researchers also did their best to provide the most reliable estimate by performing a quality assessment of studies and excluding those at particularly high risk of bias.

The main limitation is that a systematic review can only be as good as the included studies, and in this case there were few high-quality studies and a lot of variation in their findings. The included studies mainly collected data using questionnaires, which are subject to various sources of bias.

The response rate ranged from 36.3% to 89.7% and it is possible that those who respond are more likely to be experiencing pain than those who aren’t. If this was the case, then this could be an overestimate of prevalence. We also cannot tell from these findings what the cause of pain was, and whether people were receiving the appropriate management for it.

Whether the prevalence found in this review is accurate or not, living with chronic pain has a negative impact on quality of life. It can affect mobility and limit daily activity, affect employment, social and personal life, and affect mental health (e.g. depression). With an ageing population, it is likely that the prevalence will increase and the need for pain management and relief will grow.

There are a number of treatment options available on the NHS for people struggling with chronic pain, such as physiotherapy, pain management courses, and counselling.