journal of the american dietetic association

Effectiveness and safety of dietary interventions for rheumatoid arthritis:

A systematic review of randomized controlled trials

JOURNAL OFTHE AMERICAN DIETETICASSOCIATION

Smedslund et al.J Am Diet Assoc. 2010; Volume 110 (May).

Geir Smedslund, Ph.D.: Diakonhjemmet Hospital (DH)Marte G Byfuglien: DH

Sissel U Olsen: DHKåre B Hagen: DH

Study overview

Effectiveness and safety of dietary interventions for rheumatoid arthritis: A systematic review of randomized controlled trials


Background

For decades patients have used diet manipulation for possibly altering the symptoms of Rheumatoid Arthritis (RA). Diet manipulations might influence the body through several different mechanisms, like decreasing an inflammatory process, increasing antioxidant levels, changing the lipid profile, and changing the bacterial flora.

The question of benefits and harms of certain diets in RA is still a “burning question” for many patients and health care providers.


Baseline data



Objective

To assess the effectiveness and safety of dietary interventions for patients with RA when compared to usual diet.


BMI & Psychosocial measures



Methods

Types of studies: Randomized controlled trials (RCT)

Interventions:Any diet manipulation, such as elimination diets, diets labeled as Mediterranean, Cretan, any vegetarian, acid-base balance and fasting were included. Dietary supplement studies were not permitted (including fish oil supplements).


BMI & Psychosocial measures



MethodsSearch strategy for identification of studies:Relevant studies were identified by electronic searches (up to September 2006) in Cochrane Central Register of Controlled Trials, Medline, Embase, AMED and Cinahl. Reference lists of included studies and relevant reviews were scanned and authors of included studies were contacted.

Methodological assessment:Two reviewers independently assessed the trials according to: Random generation of allocation, Concealment of allocation, Co-intervention, Blinding of provider or patient, Blinding of outcome assessor, Losses to follow up and Intention-to-treat


Correlation matrix



Results

• Eight RCTs published between 1979 and 2003 with a total of 366 patients were included.

• Six trials were assessed to have moderate risk of bias, while two had high risk of bias.

• Due to insufficient data reporting and heterogeneity in interventions and outcome measures, no overall effects were calculated.


Correlation matrix



Most trials reported small to moderate beneficial effects of the experimental diet in some outcomes

Possible beneficial effects


Figure



Country, type of diet, duration of diet, number of patients, and summary effects for each of the 8 included studies

Pain, HAQ, patient global

30Elemental (1)

Denmark

13 outcome variables

53Elimination (1,5)

United Kingdom

Nsaids useDASH28, HAQ

56Cretan-Mediterran

-ian (3)

Sweden

Function, ESR, CRP

Ritchie, Grip

strength

47Elemental (1)

United Kingdom

ACR-20 response

66Vegan (12)Sweden

HAQ, pain, stiffness

Rheumatic symptoms

43Vegan (3)Finland

Radiograp. score

9 outcome variables

53Fasting+

vegetar

(13)

Norway

Pain, stiffness, Nsaid use

26Fasting+

vegetar (3)

Sweden

No difference

Beneficial effects*

No Patients

Exp. Diet (months)

Country

Pain, HAQ, patient global

30Elemental (1)

Denmark

13 outcome variables

53Elimination (1,5)

United Kingdom

Nsaids useDASH28, HAQ

56Cretan-Mediterran

-ian (3)

Sweden

Function, ESR, CRP

Ritchie, Grip

strength

47Elemental (1)

United Kingdom

ACR-20 response

66Vegan (12)Sweden

HAQ, pain, stiffness

Rheumatic symptoms

43Vegan (3)Finland

Radiograp. score

9 outcome variables

53Fasting+

vegetar

(13)

Norway

Pain, stiffness, Nsaid use

26Fasting+

vegetar (3)

Sweden

No difference

Beneficial effects*

No Patients

Exp. Diet (months)

Country

+ followed by


Figure



Outcomes for different diets. 7 to 10 days fasting followed by vegetarian diet

Study Outcome Effect Estimate (95%CI)

Sköldstam 1979 (n=25) Pain change (0 to 10) 9 weeks follow-up.

Stiffness change (0 to 10) 9 weeks follow-up

Mean difference: -0.90 [-2.98, 1.18]

Mean difference: -0 70 [-3.09,

1.69]

Kjeldsen-Kragh 1991 (n=34) Pain (0 to 10) 13 months follow-up

Physical function (HAQ*, 0 to 3) 13 months follow-up

Morning stiffness (hrs) 13

months follow-up

Mean difference: -1.89 [-3.62, -0.16

Mean difference: -0.07 [-0.48, 0.34]

Mean difference: -1.08 [-2.23, 0.07]

*Health and Activity Questionnaire


Figure



Outcomes for different diets. Vegan diet


Hafström 2001 (n = 61) Response rate ACR20 criteria 12 months follow-up

Relative risk : 8.91 [1.24, 64.30

ACR20 = American College of Rheumatology criteria for improvement in Rheumatoid Arthritis


Figure



Outcomes for different diets. Mediterranean diet


Sköldstam 2003 (n = 51) Pain (0 to 100) 12 weeks follow-up

Function (HAQ, 0 to 3) 12 weeks follow-up

Morning stiffness (min) 12 weeks follow-up

Mean difference:-14.00 [-23.63, -4.37

Mean difference: -0.20 [-0.48, 0.08]

Mean difference: -26.00 [-58.08, 6.08]

*Health and Activity Questionnaire


Figure



Outcomes for different diets. Elemental diet


Kavanagh 1995 (n=47) Function 4 weeks follow-up Mean difference:-0.80 [-4.37, 2.77]


Figure



Possible adverse effects

Although potential adverse effects were poorly reported, no severe

adverse effects were reported. However, the experimental diet was

associated with higher weight loss, total drop out rates and treatment related drop out.


Figure



Meta-analysis of the effect of dietary interventions on total dropout.


Figure



Meta-analysis of the effect of dietary interventions on treatment-related dropout.


Figure



Meta-analysis of the effect of dietary interventions on body weight


Figure



Conclusions

• The effects of dietary manipulation, including vegetarian, Mediterranean, elemental and elimination diets, on rheumatoid arthritis remain uncertain. Studies included in this analysis were small, single arm trials with moderate to high risk of bias.

• Higher drop-out rates and weight loss in the groups with dietary manipulation signal potential adverse effects that should not be ignored.


journal of the american dietetic association

Documents

experimental diet

type of diet

duration of diet

diet manipulations

usual diet

relevant studies

authors of included

identification of studies