Painful bladder syndrome/Interstitial cystitis (PBS/IC) is a clinical syndrome characterized by urinary frequency,
increased micturition frequency, urinary urgency, and bladder and pelvic pain. The causes of PBS/IC are not fully understood, and the condition is often difficult to treat. There are no established diagnostic criteria for PBS/IC, and
this has hampered the understanding of the underlying mechanisms and the development of diagnostic and treatment
methods. Bladder hydrodistention and resection or coagulation of Hunner’s lesion should be considered after treatment failure of multimodal conservative treatments. However, there is currently no established treatment for
PBS/IC. Given the situation, complementary and alternative medicine (CAM) therapies such as behavioral therapy, physical therapy, stress reduction, and dietary manipulation (DM) can be potential treatment options. This study investigated the effect of a 1.5-year intensive systematic DM (ISDM) in women with stable PBS/IC.

The study included 40 female patients (age 26-87 years; 62.3 ± 2.1 [mean ± standard error]) with PBS/IC in stable condition (duration of disease: 1.9-9.0 years; 5.3 ± 0.3).
In cooperation with the nutrition control team, we developed an original PBS/IC diet (1,500 kcal, 65 g protein, 40 g fat, 220 g carbohydrate, 1,000 ml water, 7 g salt). Data regarding daily food intake and food-related symptoms were collected by conducting a detailed interview of each patient, and we set meal menu to control PBS/IC symptoms and advised
the patients to reduce the intake of specific food items to the maximum possible extent. The following food items were removed from or restricted in the diet of patients: tomatoes, tomato products, soybean, tofu product, spices, excessive potassium, citrus, high-acidity-inducing substances, etc. We randomly assigned 30 patients to group A with instructions to follow this diet for 1.5 years (intensive systematic dietary manipulation: ISDM), and 10 patients to group B without instructions (non-intensive dietary manipulation: NIDM). We prospectively studied changes in the O’Leary-Sant Symptom Index and Problem Index (OSSI/OSPI), urinary urgency visual analog scale (VAS) score (U: 0, no urgency; 9, severe urgency), bladder/pelvic pain VAS score (P: 0, no pain; 9, worst possible pain), and quality of life (QOL: 0, very satisfied; 6, very unsatisfied) from before the start of treatment to 1.5 years after treatment. The clinical research was started after obtaining the approval from the ethics committee of our hospital. A written informed consent form was obtained from the patients after a full explanation of the purposes and procedures of the study. Statistical analysis was performed by using a t test. The significance level was set at P <.05.

No significant difference was observed in the background factors of both groups at the start of DM (Table 1). Group A showed significant improvement in all assessment items in the first 3 months after the start of treatment, and further significant improvement at 1 and 1.5 years (p<0.0001 for both). Group B showed no significant improvement in the first 3 months or at 1 year after the start of treatment; moreover, a worsening trend was observed in OSSI/OSPI and U at 1.5 years (Table 2). In addition, 6 patients in group A who received amitriptyline (100 ± 12.9 mg) before the start of DM successfully reduced the dose (58.3 ± 5.3 mg) by 1 year after treatment, while 2 patients in group B could not reduce the dose (87.5 ± 12.5 mg) after DM.

ISDM relieves various symptoms of PBS/IC and improves QOL over the long term and may also reduce the need for other treatments.

ISDM as one of the conservative treatment modality for PBS/IC should be attempted more strictly because of its noninvasiveness, without alterations to the other treatments.