THE RELATIONSHIP BETWEEN INR LEVEL AND MICROSCOPIC HEMATURIA IN ANTICOAGULATED PATIENTS

Abstract

Abstract

Introduction: Hemorhage is the most frequent and important complication of anticoagulant therapy. Sites

of bleeding include peritoneal or retroperitoneal cavity, brain, stomach, intestine and urinary tract. Urinary

tract is the most common site of hemorhage (hematuria). Hematuria can be macroscopic or microscopic and

should not be ignored. There is no consensus on the definition of microscopic hematuria, while it is generally

defined as the presence of more than five blood cells per high-power field on microscopic examination. On the

other hand some authors believe that the presence of even one red blood cell per high-power field is abnormal

and warrants further investigation. Possible causes of hematuria are numerous and range from benign urinary

system infection to malignant neoplasm. In anticoagulated patients the ratio of hematuria changes between 12-

40%. The relationship between anticoagulation and microscopic hematuria has not been well described.

International Normalized Ratio (INR) level is used to follow anticoagulated patients and it can be calculated

by dividing the observed PT to the control PT. Its level changes between 0.9-1.1. In serious cardiac disease its

level must be 2.8-3.2. The aim of this study is to determine whether there is any relation between INR level and

the incidence of microscopic hematuria.

Materials and Methods: Between January 2002 and November 2004, 933 patients were investigated and

112 of them with microscopic hematuria while on warfarin therapy were enrolled in this study. Exclusion

criterias were patients with diagnosed urologic pathology, genitourinary trauma, instrumentation,

macroscopic haematuria or the short anticoagulation period (less than 1 month). Evaluation consisted of

history, examination, routine blood tests, PTZ and INR. In addition patients underwent urinary system

ultrasound, IVP and cystoscopy. The IVP was excluded when a glomerulopathic condition was suspected from

the urinalysis. No cystoscopy was performed without endocarditis proflaxy. If daily protein excretion is more

than 1 gr, renal biopsy was taken. PSA levels were also determined and if its level was greater than 4 ng/ml

TRUS as guided prostate biopsy was undertaken. In our study, microscopic hematuria was defined as present

of five or more red blood cells per high-power field. The patients were divided into 4 groups according to their

INR values; less than 1.5, 1.5-2.5, 2.5-3.5, and greater than 3.5. The risk of bleeding attributable to

anticoagulant therapy was evaluated by comparing the frequency of bleeding in each group.

Results: A total of 91 males and 21 females with a mean age of 63 years (range 35-78) were included in the

study. In this study the ratio of microscopic hematuria was found 12%. The etiology of hematuria could not be

identified on 41 patients, while 20 of them discontinued but 21 of them are still continuing. 8 had urologic

tumor and 29 had urinary tract infection. The urologic pathology percent in each group was 83%, 75%, 55%,

and 50%, respectively. Although all patients’ drug doses were adjusted in hospital, 8 patients had an INR level

greater than 3.5.

Conclusion: The urologic pathology rate is getting lesser when the INR level is increased. Even in group 4

urologic pathology rate is 50% and one of them was bladder cancer and 3 of them were treatable

abnormalities. We therefore advocate a full evaluation, regardless of the levels of INR.