Efficacy of a Very Low Calories Ketogenic Diet in Obese Patients With Fibromyalgia or Symptomatic Knee Osteoarthritis
Phase: NA
Conditions: Fibromyalgia, Knee Osteoarthritis
Sponsor: Istituto Ortopedico Rizzoli

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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
Efficacy of a very low calories ketogenic diet (VLCKD) in obese 
patients with fibromyalgia or symptomatic knee osteoarthritis  
(KD-FM-OA) 
 
 
 
 
 
 
 
Principal Investigator 
Prof. Riccardo Meliconi 
Responsabile SSD Medicina e Reumatologia 
IRCCS Istituto Ortopedico Rizzoli  
 
Investigators 
Francesco Ursini, Dirigente Medico SSD Medicina e Reumatologia (RTD-B convenzionato 
Università di Bologna) 
Lucia Lisi, Dirigente Medico SSD Medicina e Reumatologia, IRCCS Istituto Ortopedico 
Rizzoli 
Susanna Ricci, Dietista, Servizio Dietetico, IRCCS Istituto Ortopedico Rizzoli 
Nicola Stefanelli, Dietista, Servizio Dietetico, IRCCS Istituto Ortopedico Rizzoli 
 
 
 
              
                 Signature P.I. 
 
               
 

2 
Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
SUMMARY 
 
1. INTRODUCTION 
1.1 Aim of the study 
2. STUDY DESIGN AND SETTING 
2.1 Study design 
2.2 Study setting 
3. PATIENTS 
 
3.1 General characteristics of patients 
 
3.2 Inclusion criteria 
3.3 Exclusion criteria 
4. DIETETIC INTERVENTION 
4.1 Very low-calorie ketogenic diet (VLCKD) 
4.2 Weight loss program 
5. ASSESSMENT OF DISEASE ACTIVITY 
5.1 Assessment of fibromyalgia activity 
5.2 Assessment of knee osteoarthritis activity 
6. STUDY PROTOCOL 
6.1 Study periods 
6.2 Timing of disease activity and weight assessment 
 
6.3 Ketosis assessment 
7. SAFETY MONITORING 
7.1 Blood tests 
7.2 Adverse events monitoring 
 
7.3 Women of childbearing age 
 
7.4 Insurance  
8. ETHICAL CONSIDERATIONS 
9. STATISTICAL ANALYSIS 
10. STUDY COSTS 
11. PUBBLICATION OF RESULTS  
12. SPONSOR ROLE AND RESPONSIBILITY 
13. REFERENCES 
 
 

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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
1. INTRODUCTION 
Fibromyalgia is a chronic disorder of uncertain aetiology, characterized by widespread 
pain, muscle tenderness, and decreased pain threshold to pressure and other stimuli.1 Its 
pathophysiology is still elusive, although evidence support a derangement in pain 
processing and modulation.1 Clinical manifestations of fibromyalgia encompass a large 
range of symptoms including fatigue, unrefreshing sleep, cognitive and memory 
disturbances (“fibro fog”), anxiety, depression, chronic headache, gastrointestinal 
problems and more.1  
Obesity is a well-known aggravating factor for musculoskeletal pain, such as in knee 
osteoarthritis.2 Epidemiological data show that fibromyalgia patients have higher 
prevalence of obesity (40%) and overweight (30%) and that excess of body weight 
influences course and activity of fibromyalgia.2 Similarly, obesity influences pain and 
progression of knee osteoarthritis.3 
In the last years, a new nutritional approach – namely Very Low Calorie Ketogenic Diet 
(VLCKD) – has been proposed as a potential therapeutic option in different diseases that 
shares common clinical and pathophysiological features with fibromyalgia and 
osteoarthritis.4  
The core characteristics of the VLCKD are the association of a high amount of fat, with low 
carbohydrate intake, usually a macronutrient ratio of fat to protein and carbohydrate 
combined equal to 3–4:1.4 The objective is to achieve ketosis, leading to reduced insulin 
secretion and glycaemia within 48h.4 Ketosis is achieved when less than 50 g of 
carbohydrates per day are introduced, with either restricted or unrestricted fat and calorie 
intake.5  
VLCKD have been demonstrated to provide clear clinical benefits in different diseases - in 
particular refractory epilepsy6 - and to achieve rapid weight loss in obese subjects who 
failed other dietetic interventions.7 For their efficacy and safety profile, VLCKD entered as a 
therapeutic options in recent guidelines for management of obesity.8, 9 
Furthermore, other studies evaluated the effect of VLCKD on conditions that shares 
common pathophysiological and clinical background with fibromyalgia. Accumulating 
evidence suggest positive effects on mood10, cognitive functions,11 as well as an 
improvement in nociception12 and sleep quality.13 
 
1.1 Aim of the study 
On the basis of this background, aim of this pilot study is to investigate the effects of VLCKD 
in obese patients with fibromyalgia and symptomatic knee osteoarthritis. 
 

4 
Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
2. STUDY DESIGN AND SETTING 
2.1 Study design 
Interventional study. Study procedures will be performed in agreement with current clinical 
practice guidelines8, 9. 
2.2 Study setting 
Rheumatology Outpatient Clinic, Medicine & Rheumatology Unit, IRCCS Istituto Ortopedico 
Rizzoli, Bologna. 
3. PATIENTS 
3.1 General characteristics of patients 
Adult patients with fibromyalgia or symptomatic knee osteoarthritis and comorbid obesity 
eligible to VLCKD as defined according to Italian Standards for Treatment of Obesity, 
released by the Italian Society for the Study of Obesity (SIO) and the Italian Association of 
Dietetics and Clinical Nutrition (ADI) (2016–2017)9 and  the recommendations of the Italian 
Society of Endocrinology (SIE) for VLCKD.8 
3.2 Inclusion criteria 
Age > 18 years and < 65 years 
AND 
Body mass index ≥ 30 kg/m2 
AND 
Failed to achieve weight loss with standard low-calories diet 
AND 
Any of the following conditions: 
• 
BMI ≥ 35 kg/m2 
• 
Past diagnosis of type 2 diabetes without β-cell failure 
• 
Hypertriglyceridemia (fasting triglycerides ≥ 150 mg/dL) or taking lipid-lowering medications 
• 
Hypercholesterolemia (total cholesterol > 200 mg/dL) or taking lipid-lowering medications 
• 
Past diagnosis of arterial hypertension or taking blood pressure-lowering medications 
• 
Past diagnosis of non-alcoholic fatty liver disease  
• 
Past diagnosis of heart failure class NYHA I–II 
• 
Past history of myocardial infarction (> 12 months), stroke/minor stroke (> 12 months) 
• 
Past diagnosis of carotid atherosclerosis 
• 
Past diagnosis of polycystic ovary syndrome (PCOS)  
• 
Past diagnosis of neurodegenerative disorders  
AND 
Fibromyalgia classified according to 2016 Revisions to the 2010/2011 European League Against 
Rheumatism (EULAR)/ American College of Rheumatology (ACR) criteria14 
OR 
Symptomatic knee osteoarthritis classified according to the ACR criteria15 
 

5 
Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
3.3 Exclusion criteria 
Exclusion criteria have been established on the basis of the abovementioned clinical 
practice guidelines8, 9: 
• 
Age < 18 or > 65 years 
• 
Currently pregnant or breastfeeding 
• 
Past diagnosis of type 1 diabetes mellitus, latent autoimmune diabetes in adults, β-
cell failure in type 2 diabetes mellitus, use of sodium/glucose cotransporter 2 (SGLT2) 
inhibitors (risk for euglycemic diabetic ketoacidosis) 
• 
Past diagnosis of kidney failure and moderate-to-severe chronic kidney disease, liver 
failure, hearth failure NYHA III-IV, respiratory failure 
• 
Past diagnosis of unstable angina 
• 
Recent stroke or myocardial infarction (< 12 months) 
• 
Cardiac arrhythmias 
• 
Past diagnosis of eating disorders and other severe mental illnesses, alcohol and 
substance abuse 
• 
Active/severe infections 
• 
48 h prior to elective surgery or invasive procedures and perioperative period 
• 
Past diagnosis of rare disorders: porphyria, carnitine deficiency, carnitine 
palmitoyltransferase deficiency, carnitine-acylcarnitine translocase deficiency, 
mitochondrial fatty acid β-oxidation disorders, pyruvate carboxylase deficiency 
• 
Allergy to protein-preparations ingredients  
• 
Past or current history of gallstones  
4. DIETETIC INTERVENTION 
4.1 Very low-calorie ketogenic diet (VLCKD) 
A personalized VLCKD will be prepared for each patient by specialized dietitians at IRCCS 
Istituto Ortopedico Rizzoli, Bologna using a combination of commercially-available 
ketogenic preparations and patient’s handmade prepared meals (see attachment 
“VLCKD”). The commercial preparations will be ordered for free by an authorized supplier 
(see 9) on the basis of individual choices and preferences expressed during nutritional 
interview, and delivered by the seller to the Dietetic Service – IRCCS Istituto Ortopedico 
Rizzoli, and subsequently hand-delivered to patients by a dietician investigator.  
Briefly, VLCKD is a nutritional intervention that mimics fasting through a marked restriction of 
daily carbohydrate intake, usually lower than 30 g/day (≃ 13% of total energy intake), with 
a relative increase in the proportions of fat (≃ 44%) and protein (≃ 43%) and a total daily 
energy intake < 800 kcal, depending on the amount and quality of protein preparations. 
Nonetheless, VLCKD should not be considered as a high-protein diet, since its daily protein 
intake is approximately 1.2–1.5 g/kg of ideal body weight (BMI 22.5 kg/m2).  
According to clinical practice guidelines8, 9, VLCKD is based on protein preparations of high 
biological value derived from green peas, eggs, soy and whey. Each protein preparation is 
composed by approximately 18 g protein, 4 g carbohydrate, 3 g fat (mainly high-oleic 
vegetable oils) and provides approximately 100–150 kcal. Therefore, VLCKD is characterized 
by a low lipid content, mainly deriving from olive oil (≃ 20 g per day).  

6 
Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
4.2 Weight loss program 
The weight-loss program will be preceded by a free-diet phase (Phase 0, duration: 4 weeks), 
during which the patient will be invited to eat normal meals.  
The ketogenic period will be dived in three different phases.  
During the first phase (Phase 1, duration: 4 weeks), patients are allowed to eat four to six 
(depending on ideal body weight) of such protein preparations and low-carbohydrate 
vegetables. Patients will be instructed to maintain the intake of clear liquids (water, tea, 
coffee or unsweetened carbonated drinks) > 2 L/day. 
In the next phases, the state of ketosis is still maintained, but one (Phase 2, duration: 2 weeks) 
or two (Phase 3, duration: 2 weeks) of the provided meals (lunch or/and dinner) are 
gradually replaced by natural protein meals (meat/fish/eggs/legumes).  
Following the ketogenic period, carbohydrates are gradually reintroduced, starting from 
foods with the lowest glycaemic load (fruit, dairy products—Phase 4, duration: 4 weeks), 
followed by foods with moderate (legumes—Phase 5, duration: 4 weeks) and high 
glycaemic load (bread, pasta and cereals—Phase 6, duration 4 weeks). The gradual 
reintroduction of food items allows for a progressive nutritional education that supports long-
term weight-loss maintenance. 
Nutritional details of each phase are reported in the attachment “VLCKD”. 
5. ASSESSMENT OF DISEASE ACTIVITY 
5.1 Assessment of fibromyalgia activity 
Assessment of disease activity will be performed using validated Italian language self-
administered tools (patient-reported outcomes, PROs) as suggested by the OMERACT 
proposal for Fibromyalgia Responder Index and Disease Activity Score16, including:  
1) Fibromyalgia Impact Questionnaire (FIQ)17  
2) Short-Form 36 (SF-36)18 
3) EuroQol (EQ-5D)19 
4) Hospital Anxiety and Depression Scale (HADS)20 
5.2 Assessment of knee osteoarthritis activity 
Assessment of disease activity will be performed at weekly intervals using self-administered 
PROs as suggested by the OARSI Clinical Trials Recommendations: Design and Conduct of 
Clinical Trials of Rehabilitation Interventions for Osteoarthritis.21 
1. Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index22 
2. EuroQol EQ-5D  
3. SF-36. 
 
 

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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
6. STUDY PROTOCOL 
6.1 Study periods 
As already mentioned, the study will be conducted following different periods: 
1. Free diet (4 weeks, Phase 0). After recruitment (T-4), the patient will enter “free diet 
phase” in which he/she will be asked to follow a normal free diet for 4 weeks. During 
this period, a nutritional interview will be carried out by a trained dietician who will 
elaborate a personalized diet and order the ketogenic products on the basis of 
patient’s preferences.  
2. VLCKD (8 weeks, Phases 1-3). After the free diet period, the patient will start the 
VLCKD regimen as described (4.1 and “VLCKD” attachment). At the beginning of 
this period (T0) a box with the commercial products necessary to cover the whole 
study period will be hand-delivered by a dietician that will instruct the patient on the 
correct use and storage.  
3. Maintenance (12 weeks, Phases 4-6). After VLCKD phase, the patient will start 
maintenance period as described (4.1 and “VLCKD” attachment).  
6.2 Timing of disease activity and weight assessment 
Study procedures are graphically summarized in the attachment “Study chart”.  
Patient-reported outcomes described in 5.1 and 5.2 will be obtained a T-4, T0, T1, T2, T3, T4, 
T5, T6, T7, T8, T12, T16, and T20. Patients will be instructed to fill the questionnaires at 
appropriate intervals and bring them at the subsequent office visits.  
During the office visits (T0, T8, T12, T16, T20), a rheumatologist will perform medical interview 
with special focus on adverse events and routine musculoskeletal visit; weight and height 
will be measured and recorded.  
6.3 Ketosis assessment 
Ketosis assessment will be performed using urine strips (Siemens Multistix 10 sg) provided at 
time of enrolment (T0) at weekly interval from week T0 to T12. Patients will be instructed on 
correct usage of the strips and to take a picture of urine stick that will be sent by email to a 
dedicate address for evaluation. 
7. SAFETY MONITORING 
7.1 Blood tests 
Following the abovementioned clinical guidelines8, 9, safety will be monitored through 
regular blood and urine tests: 
• 
Before VLCKD and every 4 weeks (T0-T4-T8): complete blood count (CBC), creatinine, 
blood urea nitrogen (BUN), uric acid,  glucose, HbA1c, insulin, total cholesterol, HDL-
cholesterol, LDL-cholesterol, triglycerides (serum), ALT, AST, γ-GT, total and direct 
bilirubin, Sodium, potassium, calcium, magnesium, inorganic phosphate, complete 
urinalysis and microalbuminuria, 25-hydroxyvitamin D, C-reactive protein 
• 
Before VLCKD and at the end of VLCKD (T0-T8): Body composition by whole body 
DEXA 
 

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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
7.2 Adverse events monitoring 
Adverse events will be systematically monitored during each office visits (see 6.1); any 
potential adverse event will be reported on CRF. In case of adverse event, the investigator, 
in agreement with the patient, will decide if continue or withdraw from the study. 
Furthermore, the patient and his/her general practitioner will be able to communicate to 
the study staff any suspect adverse events using the phone number reported in patient 
information sheet.  
 
7.3 Women of childbearing age 
In women of childbearing age, rapid pregnancy test will be obtained before ketogenic 
phase to exclude unacknowledged pregnancy. Patients will be instructed to immediately 
communicate to the study staff the event of unexpected pregnancy during ketogenic 
phase and to stop immediately the ketogenic diet. In this case, patient will be withdrawn 
from the study and referred for pregnancy nutritional consultation. No actions will be 
needed in case of pregnancy of a male patient’s partner. 
7.4 Insurance  
Possible damages arising from participating in the present study will be covered by  a study-
specific insurance  provided by IRCSS Istituto Ortopedico Rizzoli. 
8. ETHICAL CONSIDERATIONS 
Written informed consent will be obtained by all patients at recruitment. Study procedures 
will be performed according to the Declaration of Helsinki and clinical practice guidelines8, 
9.  
9. STATISTICAL ANALYSIS 
Given the exploratory nature of the study, an arbitrary number of 20 fibromyalgia and 20 
symptomatic knee osteoarthritis patients will be recruited from Rheumatology Outpatient 
Clinic – IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy. Patients’ associations will be 
involved for volunteer engagement.  
Primary measures of efficacy (change in FIQ total score and WOMAC total score, for 
fibromyalgia and osteoarthritis, respectively) will be compared using paired-sample 
Student’s T tests at time T-4, T0, T8, T20. Analysis of covariance (ANCOVA) will be used to 
evaluate the effect of baseline disease severity and BMI on change in primary efficacy 
measures.  
Furthermore, other exploratory analyses will be performed: 
- 
Change in secondary outcome measures at T-4, T0, T8, T20; 
- 
Correlation between change in body weight (ΔweightT0-T8) and change in primary 
(ΔFIQT0-T8 or ΔWOMACT0-T8) and secondary outcome measures; 
- 
Time course of %change in FIQ total score and WOMAC total score from T-4 to T20; 
- 
Student’s T test for difference in ΔFIQT0-T8 or ΔWOMACT0-T8 in patients who achieved 
and maintained ketosis during the ketogenic phase (urinary ketones > +5 from week 
1 to week 8) vs patient who did not maintained ketosis. 
Both per-protocol (PP) and intention-to-treat (ITT) analyses will be performed.  

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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
All analyses will be performed using the Statistical Software for Social Sciences (SPSS, IBM) 
version 23. 
10. STUDY COSTS 
No additional costs are attributable to this study except the provision for protein 
preparations required during the ketogenic phase of the diet. For this cost, we asked 
producers of VLCKD supplements a free supply of preparations to cover the requirements. 
Logistica Food srl, located in Manoppello (PE), Viale S.Tinozzi, 17 preliminary agreed (see 
attachment) to cover the requirements of the study. To preserve sensitive information of 
recruited patients, the orders covering product requirement for the entire study period will 
be anonymously placed by the Dietetic Service, IRCCS Istituto Ortopedico Rizzoli; 
subsequently the products will be hand-delivered by a dietician investigator to individual 
patients.  
11. PUBBLICATION OF RESULTS  
The results from this study will be published or shown at scientific conferences. The final 
publication of the study results will be written by the Principal Investigator. 
12. SPONSOR ROLE AND RESPONSIBILITY 
The  promoter is the sole owner of the data and is responsible of all the clinical trial activities 
from study design, development, data collection, management, analysis, interpretation of 
data, writing and the decision to submit the report for publication written by the Principal 
Investigator. 
 
 
 
 
 
 
 
 
 

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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
13. REFERENCES 
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Wolfe F, Clauw DJ, Fitzcharles MA, et al. 2016 Revisions to the 2010/2011 fibromyalgia 
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Peat G, Thomas E, Duncan R, Wood L, Hay E, Croft P. Clinical classification criteria for 
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Sarzi-Puttini P, Atzeni F, Fiorini T, et al. Validation of an Italian version of the 
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Apolone G, Mosconi P. The Italian SF-36 Health Survey: translation, validation and 
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Savoia E, Fantini MP, Pandolfi PP, Dallolio L, Collina N. Assessing the construct validity 
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Protocol: KD-FM-OA                                                                                                       Ver. 2.1 – 22/03/2021 
20. 
Annunziata MA, Muzzatti B, Altoe G. Defining hospital anxiety and depression scale 
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Fitzgerald GK, Hinman RS, Zeni J, Jr., Risberg MA, Snyder-Mackler L, Bennell KL. OARSI 
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Salaffi F, Leardini G, Canesi B, et al. Reliability and validity of the Western Ontario and 
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