Gout

Gout Care Protocol will be implemented from January 2025 – HSG GPs may refer to updates from AIC for details on the implementation of these protocols.

Background

Gout is the most common form of inflammatory arthritis. The estimated local prevalence of gout is 4.1% among Singaporean Chinese in 2012¹. It is due to deposition of monosodium urate (MSU) crystals, a result of chronic serum uric acid elevation. Gout can manifest as acute gouty arthritis, inter-critical gout and chronic tophaceous gout. While it commonly presents episodically as painful acute flares, gout is a chronic condition closely related to metabolic syndrome. Gout contributes substantial economic burden as it predominantly affects middle aged men in their productive years and is associated with considerable healthcare utilisation².

Clinical Approach

Patients with gout usually present with recurrent acute gout flares. Without appropriate treatment, the flares may increase in frequency or severity, and patients may develop chronic gouty arthritis, tophaceous gout or advanced gout, which is characterized by chronic joint pain, activity limitation, structural joint damage, and frequent flares (sometimes without full resolution of symptoms of inflammation between flares)³.

Gout is also associated with chronic kidney disease, metabolic syndrome, hypertension, type 2 diabetes mellitus, obesity, and cardiovascular diseases.⁴

Overview of the clinical approach includes:

1. Accurate gout diagnosis and consider other differentials.

2. Lifestyle management, patient education and control of risk factors.

3. Treatment of acute gout flares.

4. Early initiation of urate lowering therapy (ULT) if treatment criteria is met.

5. Screening and management of comorbidities and control of modifiable cardiovascular risk factors.

Diagnosis of Gout*

Gout can be diagnosed clinically. The following clinical features support a diagnosis of gout:

1. Acute onset of joint pain that peaks within 24hrs

2. Usually self-limiting with resolution of symptoms within 14 days

3. Podagra, which involves the first metatarsophalangeal joint (MTPJ)

4. Joint erythema / warmth / swelling

5. Previous episode(s) of similar arthritis or joint pain, with well periods between the episodes

6. Presence of tophi. Common sites include the joints of the hands or feet, helix of the ear, the olecranon bursa, and the Achilles tendon.

7. Male sex

8. Strong family history of gout

9. Patients may be able to identify triggers for the flares: acute medical/surgical illness, dehydration, alcohol intake (especially beer), purine-rich foods etc.

*Note: Asymptomatic hyperuricemia alone does not support a diagnosis of gout

Management

Management goals

Acute flares should be treated as soon as possible.
Prevent recurrent gout flares.
Lower and maintain serum uric acid level to ≤360 umol/L (6 mg/dL)⁵.
Screen for and prevent complications associated with gout (tophi, chronic arthritis, functional impairment, nephropathy).

Chronic Gout Management and Urate Lowering Therapy (ULT)

Table 1: Overview of Urate Lowering Strategies

Pharmacological

Adjunct Therapy

Non-pharmacological

1. Xanthine oxidase inhibitors (XOI)

Examples:

Allopurinol
Febuxostat (for patients who are intolerant to allopurinol)

2. Uricosuric agents

Example:

Probenecid

3.Combination therapy with XOI and uricosuric agents

Refer to Gout ACG for alternative medications.

Please refer to the Healthier SG whitelist for the full list of subsidised drugs.

Use diuretic with care

Use of losartan (if patient has concomitant hypertension)

Use of atorvastatin (if patient has concomitant hyperlipidaemia)

Dietary and lifestyle modification

Patient education

Recommended Care Components

Table 2: Summary of Recommended Care Components¹¹

Recommended Care Components	Minimum Frequency	Remarks
Serum uric acid	At baseline and thereafter as clinically indicated, as treatment requires.	Frequency of monitoring to be tailored based on clinical indication, as treatment required. If patient is treated with urate lowering therapy (ULT), repeat serum uric acid 4 to 8 weeks after dose adjustment.
Renal function monitoring	At baseline	Baseline creatinine and eGFR to assess renal function. Consider yearly monitoring if the patient is on periodic NSAID use. Frequency of monitoring to be tailored based on clinical indication.
Alanine aminotransferase (ALT), aspartate transaminase (AST)	At baseline	Baseline to exclude hepatic impairment and to detect fatty liver (feature of metabolic syndrome). If starting xanthine oxidase inhibitor (e.g. allopurinol), consider repeating 4 to 8 weeks after initiation and as clinically indicated thereafter to monitor for deranged liver function.
Full blood count	At baseline	Consider FBC to exclude infection or haematological disorders. If starting xanthine oxidase inhibitor (e.g. allopurinol), consider repeating 4 to 8 weeks after initiation and as clinically indicated thereafter to monitor for leukocytosis and eosinophilia.
Erythrocyte Sedimentation Rate (ESR)	At baseline (where applicable)	Consider ESR to exclude other suspected inflammatory arthritis. (e.g. after acute gout attack resolves).
Diabetes screening	At baseline; consider yearly thereafter.	To detect insulin resistance and diabetes mellitus (features of metabolic syndrome). Please refer to Care Protocol for Pre-Diabetes and Diabetes Mellitus.
Lipid profile	At baseline; consider yearly thereafter	To detect dyslipidaemia (feature of metabolic syndrome). All patients should be risk stratified with targets of treatment tailored accordingly. Please refer to Care Protocol for Lipid Disorders.
Weight and BMI assessment	Twice a year	Keep <23 kg/m²(for non-Asian population, keep BMI <25 kg/m²) Please refer to Care Protocol for BMI Control.
Blood pressure measurement	Twice a year	To personalise target blood pressure based on patient's risk factors. Please refer to Care Protocol for Cardiovascular Risk Assessment and Hypertension.
X-ray of relevant joints	If clinically indicated	Consider imaging to differentiate from other inflammatory arthritides.
Assessment of diet and lifestyle	Annually	All patients should be advised on low purine diet and lifestyle modification (such as alcohol avoidance and smoking cessation). Please refer to Care Protocol for Smoking Cessation.

*More frequently if clinically indicated

Consideration for Specialist Referral:

Uncomplicated gout can be managed in primary care.

Indications for specialist referral include:

Severe or refractory gout (e.g. recurrent flares despite reaching target serum urate levels with adequate ULT treatment
Difficulty in achieving the management goal with ULT, particularly with renal impairment.
Chronic kidney disease with eGFR < 30 ml/min/1.73m².
Severe adverse effects from treatment including hypersensitivity to ULT

Data Submission

The following data fields should be documented in GPs' case notes as part of good clinical practice for all patients enrolled to their practice. Submission of data fields marked with asterisks* is required for subsidy claims and Healthier SG payments.

Diagnosis

Diagnosis*
CDMP Condition(s)*
Diagnosis Year

Uric Acid

Serum Uric Acid (umol/L)
Date

Blood Glucose

HbA1c (%) OR Fasting Plasma Glucose (FPG) (mmol/L or mg/dL)
[If the patient with gout concurrently has DM OR Pre-DM OR is being screened for DM, please refer to the respective DM, Pre-DM and CVRA screening protocols for more information on whether HbA1c or FPG is tied to payments]
Date

Blood Pressure

Systolic BP (mmHg)
Diastolic BP (mmHg)
Date

Lipid Profile

LDL-C (mg/dL or mmol/L)
HDL-C (mg/dL or mmol/L)
Triglycerides (mg/dL or mmol/L)
Total Cholesterol (g/dL or mmol/L)
Date

[If the patient with gout concurrently has hyperlipidaemia OR is being screened for lipid disorders, please refer to the respective Lipid Disorders and CVRA screening protocols for more information on whether the above fields are tied to payments]

Kidney Assessment

Serum creatinine (µmol/L) OR eGFR (ml/min/1.73m²)
Date

Weight

BMI (kg/m²), calculated from height*, weight*
Waist circumference (in cm; mandatory to fill if weight is not feasible. Otherwise, optional field to fill)*
Weight not feasible (if applicable)*
Date*

Financing

CHAS/PG/MG cardholders who are Healthier SG enrollees can opt to use the Healthier SG Chronic Tier at their enrolled clinics, which provides percentage-based subsidies for selected chronic medications sold within the stipulated price caps. When making claims for these medications, GPs will need to submit the quantities and selling prices for the drug product prescribed.

Details on the GP Annual Service Fee for enrollees with Gout can be found in the Healthier SG Enrollment Programme Agreement.

References