Can pain affect your HbA1c (A1c)? If you are living with both chronic pain and diabetes, this is an important question — and the answer is yes, it can, though the relationship is indirect. Chronic pain triggers physiological stress responses, disrupts sleep, reduces physical activity, and can make diabetes self-management considerably harder. All of these effects may gradually push blood glucose levels higher, ultimately showing up in your HbA1c result. This article explains the mechanisms involved, other factors that can alter HbA1c readings, when to seek medical advice, and practical steps to manage pain in ways that support better diabetes control.

How Chronic Pain Can Affect Blood Sugar and HbA1c Levels

Chronic pain places the body under sustained physiological stress, which can disrupt glucose regulation and lead to behavioural changes — such as reduced activity and poor sleep — that may raise HbA1c over time.

HbA1c (glycated haemoglobin) is a blood test used widely across the NHS to measure average blood glucose levels over the preceding two to three months. In the UK, HbA1c is reported in mmol/mol (you may also see older percentage figures, but mmol/mol is now the standard). It is a cornerstone of diabetes monitoring and management. Many people living with both diabetes and chronic pain wonder whether their pain condition could be influencing their HbA1c readings — and the answer is: it may do, though the relationship is indirect rather than direct, and the degree of effect varies considerably between individuals.

Chronic pain — whether from conditions such as osteoarthritis, fibromyalgia, neuropathy, or lower back pain — can place the body under sustained physiological stress. This ongoing stress response may disrupt normal metabolic processes, including glucose regulation. People living with persistent pain may also experience significant changes in their daily behaviour, such as:

• Reduced physical activity due to pain-related mobility limitations

• Disrupted sleep patterns, which are closely linked to insulin resistance

• Changes in appetite and diet, including increased consumption of comfort foods high in refined carbohydrates

• Reduced motivation or capacity to self-manage diabetes effectively

All of these secondary effects can contribute to elevated blood glucose levels over time, which may ultimately be reflected in a higher HbA1c result. It is important to understand that pain does not chemically alter the HbA1c test itself, but its systemic effects on the body and behaviour can meaningfully shift the result in some people. Recognising this connection is an important step in holistic diabetes care.

Sources: NHS HbA1c test information; Diabetes UK — Stress and blood sugar.

The Link Between Stress Hormones, Pain, and Glucose Control

Persistent pain can activate the HPA axis, elevating cortisol and adrenaline; these hormones promote gluconeogenesis and insulin resistance, potentially raising blood glucose and HbA1c.

The physiological mechanism connecting pain and blood glucose lies primarily in the body's stress response system. When the body experiences pain — particularly persistent pain — it can activate the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system. This may trigger the release of stress hormones, most notably adrenaline (also known as epinephrine) and cortisol.

These hormones are part of the classic 'fight or flight' response and have well-established effects on glucose metabolism:

• Cortisol stimulates gluconeogenesis (the production of new glucose in the liver) and promotes insulin resistance in peripheral tissues, meaning cells become less responsive to insulin's signal to absorb glucose.

• Adrenaline promotes the breakdown of glycogen (stored glucose) in the liver, rapidly raising blood glucose levels.

In acute situations, this response is protective. In the context of chronic pain, however, the stress response system can become dysregulated — in some people this means intermittently or persistently elevated stress hormones, while in others the HPA axis may become blunted over time. The net effect on glucose control therefore varies between individuals. Where stress hormone activity is increased over weeks and months, this pattern of elevated blood glucose may be captured by the HbA1c test, potentially pushing results above target ranges.

Additionally, chronic psychological distress — which frequently accompanies persistent pain — can further influence cortisol activity. Depression and anxiety, both common in chronic pain conditions, are independently associated with poorer glycaemic control. NICE guideline NG28 acknowledges the bidirectional relationship between mental health and long-term condition management, reinforcing the importance of addressing psychological wellbeing as part of comprehensive diabetes care.

Sources: NICE NG28 (Type 2 diabetes in adults: management); Diabetes UK — Stress and blood sugar.

Other Factors That Can Alter Your HbA1c Result

Iron deficiency anaemia, haemolytic anaemia, CKD, pregnancy, haemoglobinopathies, and medicines such as corticosteroids can all cause falsely high or low HbA1c results, independent of actual glucose levels.

While pain and stress may influence blood glucose control, it is equally important to be aware that several other factors — unrelated to actual blood glucose levels — can cause the HbA1c result to appear falsely high or falsely low. Clinicians and patients should consider these when interpreting results.

Factors that may falsely raise HbA1c:

• Iron deficiency anaemia (reduced red blood cell turnover, prolonging cell lifespan)

• Vitamin B12 or folate deficiency

• Certain haemoglobin variants or haemoglobinopathies (effect depends on the assay method used and red blood cell lifespan)

Factors that may falsely lower HbA1c:

• Haemolytic anaemia (increased red blood cell destruction shortens cell lifespan)

• Recent blood transfusion

• Pregnancy (particularly in the second and third trimesters)

• Certain haemoglobin variants or haemoglobinopathies (again, assay- and lifespan-dependent)

Chronic kidney disease (CKD) can make HbA1c unreliable — the direction of the effect (higher or lower) varies depending on the assay method used and changes in red blood cell lifespan. If you have CKD, your diabetes team may discuss alternative monitoring approaches with you.

If you have a known haemoglobinopathy or another condition that may affect HbA1c reliability, your GP or diabetes team can liaise with the local laboratory about the assay method being used. In some circumstances, alternative measures of glucose control — such as self-monitoring of blood glucose, continuous glucose monitoring (CGM) or flash glucose monitoring, or occasionally fructosamine (subject to local policy) — may be more appropriate.

Medications can also play a role. Corticosteroids (e.g., prednisolone) are well known to raise blood glucose significantly and will therefore elevate HbA1c with prolonged use. This is a direct pharmacological effect: corticosteroids promote gluconeogenesis and reduce insulin sensitivity. If you have been prescribed a course of steroids, it is important to discuss the potential impact on your diabetes control with your GP or diabetes team, as more frequent glucose monitoring and temporary adjustments to your diabetes treatment may be needed (see the Joint British Diabetes Societies for Inpatient Care [JBDS-IP] guideline on steroid-induced hyperglycaemia for clinical detail).

Some medicines used for neuropathic pain — such as pregabalin and gabapentin — can cause weight gain, which may indirectly affect glycaemic control over time. Discuss any concerns about your medicines with your prescriber.

If you suspect a medicine is causing you side effects, you can report this via the MHRA Yellow Card scheme (available at yellowcard.mhra.gov.uk).

Sources: RCPath/NHSE guidance on HbA1c use and limitations; NGSP HbA1c assay interference resource; JBDS-IP guideline on steroid-induced hyperglycaemia; NICE NG28.

When to Speak to Your GP or Diabetes Team About Your HbA1c

Contact your GP or diabetes team if your HbA1c has risen unexpectedly, pain is affecting your self-management, or you have been prescribed corticosteroids without glucose monitoring guidance.

If you are living with chronic pain and have noticed a rise in your HbA1c — or if your diabetes has become harder to manage — it is important not to dismiss this as inevitable. There are clear situations where prompt contact with your GP or diabetes care team is warranted.

Consider contacting your GP or diabetes team if:

• Your HbA1c has risen unexpectedly, particularly if your diet and medication have not changed

• You are experiencing new or worsening pain that is affecting your sleep, activity levels, or ability to self-manage your diabetes

• You have been prescribed corticosteroids and have not been given guidance on monitoring your blood glucose

• You are experiencing symptoms of hyperglycaemia, such as increased thirst, frequent urination, fatigue, or blurred vision

• You feel that depression, anxiety, or low mood related to your pain may be affecting your diabetes management

Seek urgent medical advice — contact your diabetes team, call NHS 111, or call 999 in an emergency — if you experience:

• Very high blood glucose with vomiting, abdominal pain, rapid or difficult breathing, or confusion (possible signs of diabetic ketoacidosis [DKA] or hyperosmolar hyperglycaemic state [HHS])

• If you have type 1 diabetes and your blood glucose is high, check your ketones as directed by your diabetes team and follow their sick-day rules

Do not delay seeking help if you are unsure — DKA and HHS are medical emergencies.

Regarding routine monitoring: NICE guideline NG28 recommends that HbA1c is measured every three to six months when treatment is being adjusted, and every six months once stable. If pain or other life circumstances are creating instability in your glucose control, more frequent monitoring may be appropriate. For people with type 1 diabetes, NICE guideline NG17 provides specific guidance on HbA1c monitoring frequency and ketone testing.

Your diabetes team can also refer you to relevant support services, including pain management clinics, psychological therapies (such as those available through NHS Talking Therapies), and structured diabetes education programmes such as DESMOND or DAFNE, which can help you regain confidence in managing your condition.

Sources: NICE NG28 (Type 2 diabetes in adults: management); NICE NG17 (Type 1 diabetes in adults); NHS pages on hyperglycaemia, DKA and HHS.

Managing Pain Effectively to Support Better Diabetes Control

A multidisciplinary approach to chronic pain — including supervised exercise, CBT, and improved sleep — can reduce stress hormone activity and support better HbA1c and overall diabetes management.

Addressing chronic pain is not only important for quality of life — it may also have a meaningful positive impact on your HbA1c and overall diabetes management. A multidisciplinary approach, as recommended by NICE guideline NG193 on chronic primary pain, is generally most effective and may include a combination of pharmacological and non-pharmacological strategies.

Non-pharmacological approaches recommended or supported by NICE include:

• Supervised exercise and physiotherapy — even gentle, low-impact activity such as swimming or walking can reduce pain, improve insulin sensitivity, and support better glucose regulation

• Cognitive behavioural therapy (CBT) and acceptance and commitment therapy (ACT) — recommended by NICE NG193 for chronic primary pain and effective for the psychological distress that can worsen glycaemic control

• Improved sleep hygiene — addressing sleep disturbance can reduce insulin resistance and support better glucose regulation

• Mindfulness-based approaches — some people find these helpful for pain coping and stress management; evidence is emerging, and they may be offered as part of a broader pain management programme, though they are not specifically recommended as a standalone treatment in NICE NG193

An important note on pain medicines: NICE guideline NG193 does not recommend opioids or gabapentinoids (such as pregabalin or gabapentin) for chronic primary pain, unless under specialist advice or where there is a separate clinical indication. If you are currently taking these medicines, do not stop them without speaking to your prescriber, but do discuss whether they remain appropriate for you.

From a pharmacological perspective, corticosteroids can significantly raise blood glucose with prolonged use. If you are prescribed steroids for pain or another condition, your GP or diabetes team should advise you on increased glucose monitoring and whether temporary adjustments to your diabetes treatment are needed, in line with JBDS-IP guidance on steroid-induced hyperglycaemia.

Certain antidepressants used for neuropathic pain (such as amitriptyline or duloxetine) may have modest effects on weight or appetite, which could indirectly influence glucose control over time. Always discuss any new medication with your prescriber in the context of your diabetes. If you suspect a medicine is causing side effects, report this via the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

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Ultimately, the relationship between pain and HbA1c underscores the importance of treating the whole person rather than individual conditions in isolation. Working collaboratively with your GP, diabetes nurse, and pain specialist — and communicating openly about how pain is affecting your daily life — is the most effective path towards achieving both better pain control and a healthier HbA1c.

Sources: NICE NG193 (Chronic primary pain); JBDS-IP guideline on steroid-induced hyperglycaemia; Diabetes UK — Stress and blood sugar; NHS Talking Therapies.

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