乳がん体験者の術後上肢機能障害に対する主観的認知尺度の作成と信頼性および妥当性の検討

Development of an Instrument for the Evaluation of Subjective Perception of Postoperative Functional Impairment of the Arm in Breast Cancer Survivors

要旨

　本研究は乳がん体験者の術後上肢機能障害に対する主観的認知尺度を作成し，信頼性および妥当性を検討することを目的とした．尺度原案は文献および乳がん体験者，医師，作業療法士を対象とした面接調査による質的なデータを基盤として，5段階のリッカート尺度をもつ腫脹，痛み，肩関節可動域の縮小，知覚鈍麻，筋力の低下，皮膚のひきつれ感に関する12項目で作成した．次に看護研究者9名と看護実践者8名を対象に尺度原案の内容妥当性を検討し，3項目加えて15項目にし，修正した．信頼性および妥当性の検討を目的とした調査は2回実施し，被験者1が56名，被験者2が150名を対象とした．その結果，尺度のCronbach's α係数は0.88〜0.92であり，項目と全体の相関係数は被験者1の調査でr_s＝.41〜.80（p＜.01），被験者2でr_s＝.37〜.84（p＜.01）と有意な相関が認められ，内的整合性が確認された．因子分析では1因子が抽出されたが，治療や看護が異なる15項目を個別に捉える尺度として分析した．日本版上肢障害評価表との相関係数はr_s＝.26〜.71（p＜.01〜.05）で，5〜26項目と有意な正の相関がみられた．VASとの相関係数はr_s＝.25〜.50（p＜.01〜.05）で有意な相関がみられ，基準関連妥当性が確認された．また，表面妥当性は支持された．臨床的妥当性の検討では，尺度15項目が14.0〜69.3％の対象者に認知されていた（被験者2）．したがって，本尺度の信頼性および妥当性は保持されていると考えられた．今後，本尺度は乳がん体験者の身体状況を測定する研究や，術後上肢機能障害の予防緩和に向けた介入のアセスメントツールの一つとして活用が可能であろう．

Abstract

　The purpose of this study was to develop an evaluation scale for the subjective perception of postoperative functional impairment of the arm in breast cancer survivors, and to assess the reliability and validity of that scale. The draft scale was first prepared based on published literature and qualitative data obtained from interviews with breast cancer survivors and physicians and occupational therapists involved in their treatment. It comprised 12 items, each graded on a 5.point Likert scale: assessing swelling, pain, limited mobility or frozen shoulder, numbness, weakness, and tightness, pulling, and/or stretching. Nine researchers in the nursing field and 8 practicing nurses then evaluated the content validity of the draft scale, leading to the addition of 3 new items, for a total of 15 items. Reliability and validity were evaluated through two surveys, a preliminary survey targeting 56 breast cancer survivors, and a main survey targeting 150 survivors. The results demonstrated internal consistency: Cronbach's alpha was 0.88 to 0.92, and the correlation between individual items and the whole scale was significant in both test 1(correlation coefficient r_s=.41 to .80 [p＜.01])and test 2(r_s=.37 to .84 [p＜.01]). Although one factor was identified based on factor analysis, the scale was analyzed separately for each of the 15 items, which differed in terms of treatment or nursing. The correlation with the Disabilities of the Arm, Shoulder and Hand questionnaire was significant(r_s=.26 to .71 [p＜.01 to .05]), indicating significant correlation in 5 to 26 out of 30 items. The correlation with the VAS questionnaire was significant(r_s=.25 to .50 [p＜.01 to .05]), supporting criterion.related validity. Face validity was also supported. Evaluation of clinical validity indicated that 15 items were observed within the range of 14.0 . 69.3% of the subjects. Analytical results may support the reliability and validity of the scale. This scale will be useful for research to determine physical conditions, and/or as an assessment tool for prevention and palliative care of postoperative functional impairment of the arm in breast cancer survivors.