Data extraction and study selection

Data extraction was carried out independently by two authors using standard data extraction forms. In cases where more than one publication of a single study group were found, results were grouped together and relevant data from each report were used in the analyses. Data on the primary and secondary outcomes as stated above was extracted. Patient characteristics (including demographic information and comorbidities) from the different studies included and excluded from the analysis were noted in a tabular form (Tables ​(Tables11,​,2).2). All disagreements were resolved by the fourth and fifth authors.

Patients and yoga intervention characteristics of randomized controlled trials evaluated in this meta-analysis

y = 29,

c = 30

Classes were run by an experienced yoga teacher who used judgement to adapt the exercises to the needs and abilities of the participants.

The exercises focused primarily on breathing and relaxation (pranayama) but also included gentle stretching and postures (asanas).

Twice-weekly 90-min yoga class (total 24).

Control group was waiting list for yoga class.

Primary outcome - HbA1c. Secondary outcome measures -

(a) blood glucose levels before and after each yoga session; (b) UKPDS cardiovascular risk score (a composite of blood pressure, smoking status, lipid ratio, presence of atrial fibrillation, and HbA1c); (c) BMI; (d) waist circumference;

(e) ADDQoL; (f) MYMOP; (g) self-efficacy; (h) attendance

Measures were taken at baseline, immediately on completion of the yoga class (or control period), and six months later

n = 120

y = 60

c = 60

Comprehensive yogic breathing program with Sudarshan Kriya yoga plus standard therapy for diabetes versus standard therapy only for control group

The SKY group patients underwent a comprehensive yogic breathing program for 3 days. This course included yogic movements and postures (asanas),

relaxation practices, meditation, group processes and

discussion of stress-relieving principles. Patients underwent

1 h of long group breathing technique, which included

three stages of Pranayam, three rounds of 20 each of

Bhastrika, three times Om chanting and Sudarshan Kriya (long kriya) followed by rest in supine position on the first and second day. On the third day, they were taught the short breathing technique, which included three stages of Pranayam, three rounds of 20 each of Bhastrika, three

times Om chanting and Sudarshan Kriya (short kriya) followed by rest in supine position. This process took a

total of 25–35 min and was learnt under the guidance of

a certified teacher. (As per first article - Jyotsna 2012 et al.)

SKY group continued the standard treatment and practice of short

kriya daily at home. To ensure home practice, they were asked to fill a follow-up book in which they marked the

days on which they did SKY and got it countersigned by a

relative or attendant. They were required to come weekly for group Sudarshan Kriya Yoga and Pranayam (long kriya) to a center in the hospital and get the follow-up book signed by the yoga teacher each time they attended.

y = 77,

conventional PT – 77,

c = 77

Hatha yoga and conventional PT exercise were trained for 24 weeks in basic exercise techniques, diabetes education and instructions

Yoga class was designed by a certified Hatha yoga instructor attend one yoga class weekly was conducted for 24 weeks along with home exercise.

Each yoga session consisted of 20 min of pranayamas (breath-control exercises), 25 min of dynamic warm-up exercises, 60 min of asanas (yogic postures), and 15 min of supine relaxation in savasana (corpse pose).

The conventional PT exercises consisted of one class (2 h) per week for 24 weeks along with home exercise. The conventional PT sessions consisted of 15 min of warm up exercises, 30 min of aerobic walking on an outdoor 400-m track, 20 min of body flexibility exercises, 20 min of aerobic dance, 25 min of games and 10 min of warm down exercises. Daily home exercise 3–4 times per week for 1 h in the same Rate of Perceived Exertion was encouraged for subjects in both the Hatha yoga and conventional PT exercise classes.

1 class per week for 24 weeks

Daily home exercise 3–4 times per week for 1 h in the same Rate of Perceived Exertion was encouraged for subjects in both the Hatha yoga and conventional PT exercise classes.

Fasting blood glucose (FBG), serum total cholesterol (TC), triglycerides, low-density lipoprotein (LDL), very low-density lipoproteins (VLDL) and high-density lipoprotein (HDL).

The oxidative stress indicators were (malondialdehyde – MDA, protein oxidation – POX, phospholipase A2 – PLA2 activity) and oxidative status [superoxide dismutase (SOD) and catalase activities]. All were measured at 0, 3 and 6 months.

y = 62,

c = 62

Neck movements

Hands stretch breathing Elbow flexion and extension Wrist movements

Waist rotation

Knee movements

Leg stretch and movements Tadasana breathing

Kati chakrasana breathing

Suryanamaskara

3 rounds with breathing

A kara (3 rounds)

U kara (3 rounds)

M kara (3 rounds) A-U-M kara (3 rounds)

Shavasana

Yoga Nidra & A-U-M Chanting

y = 37

r + y = 38

c = 37

The pranayama-related techniques were practiced by the participants each evening before going to bed.

Ayurveda herbal juices in additional to yoga was given in one of the intervention groups.

The control group did not receive any intervention.

y = 24

c = 24

Each class consisted of: guided meditation and breath-work, active and passive asanas (including standing, sitting, twists and restorative postures), and guided relaxation. Participants were encouraged to practice yoga at home and workbooks, props and a DVD were provided to aid home practice.

Standard Exercise (SE) consisted of a 60-min session twice weekly for 12 weeks to match the dose and duration of the yoga condition. Sessions were held at a gym-type facility that included an indoor walking track, treadmills, ellipticals, and stationary bicycles. Each session included a 5-min warm-up (i.e. stretches), 50 min of moderate-intensity exercise and a 5-min cool-down.

Primary outcomes assessed feasibility and acceptability, including enrolment rates, attendance, study completion, and participant satisfaction. Secondary outcomes included HbA1c, physical activity, and measures of diabetes-related emotional distress, self-care and quality of life (QOL).

Assessments were conducted at baseline, end of treatment, 6-months and 9-months post-enrolment.

y = 32

p = 33

c = 35

The 60 min sessions consisted of 25 min-Surya namaskara-12 steps, 5–7 min Deep relaxation-Muscle relaxation technique, 15 min Asana or yoga postures. The postures consisted of Pava- namuktasana in the supine position, Bhujangasana and Shalabhasana in the prone position, Ardhamatsyaendrasana in the sitting position as recommended by yoga experts for diabetes. This was followed by 15 min of pranayama. On the other days the women were instructed to practice at

home and maintain a daily log.

Each peer mentor would visit 13–14 women with diabetes. A face to face meeting with the woman with diabetes in a week for about 45–60 min on assistance in applying disease management or prevention plans in daily life, providing emotional and social support and proactive flexible ongoing support. This was followed up by a telephone call in the same week. A monthly review of the activities was also undertaken by the principal investigator.

The control group was given the usual standard of care including continuing oral hypoglycaemic drugs, advise on diabetic diet and exercise for at least 10 min a day to a level of 150 min/week.

Primary outcomes studied were fasting plasma glucose, HbA1c, quality of life and pharmacological adherence.

Adherence to drugs was measured by Morisky Medication adherence scale (MMAS–8) in local language.

The secondary outcomes studied were BMI and waist hip ratio (WHR), blood pressure and total cholesterol (the last two were added later as funds became available)

(10) Bairy S et al.

Vijayawada, India [22].

y = 78

c = 83

3- month residential naturopathy intervention program comprising diet, yoga, hydriatic treatments, massage, and didactic and interactive lectures on lifestyle modification and type 2 diabetes mellitus self- management. Patients underwent a structured routine which involved physical activity, yoga program with asanas, pranayama, meditation and relaxation, calorie restriction, and salt-restricted diet. The diet prescribed was a low glycemic index, low-salt high-fiber plant-based diet containing whole grains, legumes, vegetables, and fruits with no added oil, sugar, or salt. They also underwent short intermittent juice fasting with calorie restriction over 3–4 days a month. They had to undergo a structured routine of hydriatic treatments such as hip bath, immersion bath, jets, sprays, douche, and mud and steam bath apart from partial and full-body Swedish massages.

The control group received conventional antidiabetic treatment as per the standard guidelines. They also received a diabetes self-management program by a diabetes educator during their hospital visits.

Primary outcome – HbA1c, Secondary outcome – Fasting blood glucose, postprandial blood glucose,

Medication score using Diabetes Medication Satisfaction Tool,

Parenteral medication (insulin) score. Assessment done at baseline, 3, 6, and 12 months

(11) Vaishali K, et al.

Mangalore, India [23].

y = 27

c = 30

y = 20

c = 18

1. Didactics—10 min

Diabetes causes, complications and lifestyle factors

Principles, philosophy, and practices related to a yoga based lifestyle program

Stress response

Maladaptive 23ehaviour and 23ehaviour change Emotion and coping

2. Pranayama (Breathing exercises)—6 min Hands stretch breathing

Ankle stretch breathing

Tiger breathing

Rabbit breathing

3. Loosening exercises (any 3)—10 min Jogging

Forward, backward, side bending

Twisting

Pavanamuktasana kriya (Supine knees to chest) Surya namaskara (3 sun salutations)

4. Standing asana (any 3)—8 min Padahasthasana (Foot hand) Ardhachakrasana (Half moon) Trikonasana (Triangle) Parshvakonasana (Side angle) Ardhakati chakrasana (Half wheel) Vrikshasana (Tree)

5. Supine asana—8 min

Sarvangasana (Shoulder stand)

Halasana (Plough)

Matsyasana (Fish)

Pavanamuktasana (Supine knee chest position) Naukasana (Boat)

6. Prone asana—8 min

Bhujangasana I, II, III (Cobra)

Shalabhasana – alternate legs, both (Locust) Dhanurasana (Bow)

Navasana (Boat)

7. Sitting asana—8 min Paschimottanasana (Seated forward bend) Vakrasana/ardhamatsyendrasana (Half twist) Ustrasana (Camel)

Sashankasana (Rabbit)

8. Relaxation Shavasana (Corpse) with guided scan—6 min

9. Chanting ‘OM’ monosyllables, primordial sounds in Indian philosophy

Both yoga and the control group attended the same day long (eight hour) group counselling session on lifestyle changes with their spouses. The control group was asked to do 30 min of walking plus breaks for rest on three to six days per week during each of the eight weeks of the study. Including rest breaks, the total time was approximately equivalent to the 75 min yoga class.

At least three, and up to six, yoga classes per week over the eight weeks of the study. Yoga classes were offered on six days of each week.

Each class lasted 75 min

Participants were asked to do a home practice if they were unable to attend at least three classes in a given week and were asked to keep track of each home practice in a daily diary.

Y = 50

c = 50

The experimental group was taught a series of yoga postures in groups of 25 patients each. They were instructed to practise them daily for 1 h duration and were asked to record the number of minutes they engaged in yoga per day.

At the end of 2 weeks of supervised yogic training each subject was given advice on ongoing medical treatment and was given a booklet illustrating personalized yoga program to practice regularly at home.

y yoga, c control, PT Physical exercise therapy, r = rasahara (ayurvedic juices), p = peer support

Patients and yoga intervention characteristics of randomized controlled trials excluded from this meta-analysis

(1) Ebrahimi M et al.

Semnan, Iran [26].

y = 15

a = 13

c = 11

1 Pawanmuktasana – 10 min

2. Salabhasana, virabhadrasana, Trikonasana, Upavistha Konasana, vrikshasana, Padahastasana, uttanasana, vajrasana, vakrasana, gomukhasana, paschimottanasana, uttanpadasana, bhujangasana, salabhasana, dhanurasana, viparita karani – 30 min

3. Surya namaskar – 20 min

4 Sitkari and bhramari pranayama – 15 min

5.Nadi shodhana, kapalbhati, and Shavasana – 10 min

6. Yoga nidra – 5 min

Aerobic exercise included running on a treadmill. For first four weeks, exercise performed for 25 min with 60–65% of the maximum heart rate reserve (MHRR). During second four weeks, time of exercise was 30 min with an intensity 60–65% of the MHRR, and for third four weeks, time increased to 35 min and intensity raised up to 70–75% of the MHRR. The calculation of the exercise intensity was done using Karvonen formula.

12 weeks

3 sessions every week (90 min)

(3) Sharma R et al.

Gaya district of Bihar [27]

B1 (lifestyle modification and Yoga

along with allopathic medication) = 13

B2 (Ayurveda medication, lifestyle

modification and Yoga along with allopathic medication) = 2529

Cohort A1 and A2 included prediabetics only = 502

Yogasana

Surya Namaskar, Tadasana, Katichakrasana, Sarvangasana, Halasana, Matsyasana, Ushtrasana, Gomukhasana, Ardha Matsyendrasana, Mandukasana, Paschimottanasana, Pawanmuktaasana, Bhujangasana, Shalabhasana, Dhanurasana, Vajrasana, Shavasana

Pranayama

Nadi Shodhana, Suryabhedi, Bhastrika

Kriya

Kunjal,

Agnisara Kapalabhati,

1. FBS and PPBS at baseline and the 6th month

2. Subjective symptoms of diabetes such as polyuria, polydipsia, polyphagia, weakness, non-healing ulcer and blurred vision of the individual patients were measured on following scoring:

Absent: 0

Mild: 1 Moderate: 2 Severe: 3

Randomisation strategy not clear.

Control group not receiving yoga absent in the study

(4) Sreedevi A et al.

Njarackal, Ernakulam district, Kerala, India [28]

y = 31

p = 26

c = 26

The 60 min sessions consisted of 25 min-Surya namaskara-12 steps, 5–7 min Deep relaxation-Muscle relaxation technique, 15 min Asana or yoga postures. The postures consisted of Pava- namuktasana in the supine position, Bhujangasana and Shalabhasana in the prone position, Ardhamatsyaendrasana in the sitting position as recommended by yoga experts for diabetes. This was followed by 15 min of pranayama. On the other days the women were instructed to practice at

home and maintain a daily log.

Each peer mentor would visit 13–14 women with diabetes. A face to face meeting with the woman with diabetes in a week for about 45–60 min on assistance in applying disease management or prevention plans in daily life, providing emotional and social support and proactive flexible ongoing support. This was followed up by a telephone call in the same week. A monthly review of the activities was also undertaken by the principal investigator.

The control group was given the usual standard of care including continuing oral hypoglycaemic drugs, advise on diabetic diet and exercise for at least 10 min a day to a level of 150 min/week.

Another paper from the same group elaborating on the primary outcomes (FPG, HbA1c) has already been included (vide supra)

This paper exclusively provides data on impact of yoga on different aspects of quality of life (QOL) only, and hence excluded

(5) Nagarathna R. et al.

India [29]

y = yoga, c = control, a = aerobic exercise; RCT Randomized controlled trial, LDL Low density lipoprotein, HDL High density lipoprotein, VLDL Very low density lipoprotein